How many ways are there to manage your task list? Almost as many as there are people with tasks to do. Here are 20 different ways of tracking your to dos, with examples of each.

You probably use more than one of these options, depending on what you’re trying to manage and what suits your temperament. Or maybe you have some other ideas. If so, share them here.

1. Free web-based to do list managers. Remember the Milk supports sharing lists, email add of tasks, and SMS reminders. Ta-da List is 37Signals’ stripped-down version of their for-pay Backpack information manager. Voo2Do includes project management capabilities like support for software scheduling and tasks organized by project.

2. The Hipster PDA. A pile of index cards held together with a small binder clip plus a Fisher Space Pen as a stylus. Carry it in your pocket. Take notes on the cards. Categorize using rainbow-colored cards. Reorder as necessary. Learn more on the Hipster PDA wiki.

3. Text files. You can put everything in one big text file. You can implement GTD with text files. If you get really excited about your text files, try the Todo.txt scripts that give you powerful editing, searching, sorting, and progress reporting.

4. Task list integrated with your desktop or online calendar. The 30 Boxes online calendar offers taggable to do lists. Yahoo’s calendar incorporates a simple task list. Microsoft Outlook, Microsoft Entourage, and the Mac’s iCal software all offer task management capabilities.

5. Word processor or spreadsheet, desktop or online. Of course you can use Microsoft Office or OpenOffice. Create task lists that look just as you want, print them out, and get the tactile pleasure of scribbling off tasks as you complete them. Online versions make it super-easy to share lists with your family members or coworkers, like when you want to add items to the grocery list. Two biggies in this category are Google Docs & Spreadsheets and Zoho Office.

6. The Emergent Task Planner. PDF files that you print out. Developed by David Seah, these pages guide your work each day using time boxing. You list what you need to do, estimate how long each will take, and schedule them in blocks of time.

7. To do list widget on an Ajax start page. I like Netvibes’ to do list module. When you check off an item, it remains on the list, but crossed out, giving you feel-good feedback as to what you’ve completed. But you don’t have to use an actual task list widget. The start pages offer various sticky notes and text editor widgets that could be used also.

8. Paper-based 1980s-era planner. Remember Filofax? The Franklin Planner? No self-respecting Gordon Gekko wannabe of the late eighties would be without a bulging binder of to dos and calendar items and contacts. Then the Palm Pilot came along and it was named the “Filofax of the nineties.” Now paper planners are still used, but they no longer qualify as status symbols.

9. Desktop note taking app. You might use this as an intermediate spot between your brain and a more structured to do list or project planner. Check out our profile of four of them: Sidenote and mynotes on the Mac, EverNote and OneNote on Windows. Readers also mentioned VoodooPad (Mac), Yojimbo (Mac), and Tomboy (Linux) among possibilities to consider.

10. Build-your-own custom online to do list manager with Dabble DB, Ning, or Coghead. This new breed of do-it-yourself web app platforms make it easier than ever before to create sharable online software. Creating a to do list app would be a good way of checking out how capable these services are.

11. Sticky notes everywhere. Not electronic stickies–real stickies. They’re not ideal as a primary means of managing tasks but come on, admit it, haven’t you put a sticky note on the bezel of your computer monitor to remind yourself to do something? I also put stickies on the front door when I need to remember to take something with me the next time I leave. Plus, sticky notes are great for doing preliminary project planning–write each task on a sticky note, perhaps categorized by color–and shift them around on a big board to see how tasks fit together.

12. Mind mapping. Feeling stuck in a rut? Not making progress on your goals? Mind mapping can open up new ways of thinking about how you should move forward. You can doodle a mind map on a piece of paper or use mind mapping software. You can choose from open source (e.g., FreeMind), freeware or shareware (e.g., Compendium), or for-purchase (e.g., MindManager).

13. Open-source personal information manager (PIM) on your own web server. Perfect for someone who knows how to hack and wants to customize their information management. Tudu lists is available as source code or in a hosted version. Tracks, built in Ruby, implements GTD and can be installed as desktop software because it comes with a built-in webserver. Gravity GTD also implements GTD.

14. Fancy notebook with a fancy pen. If you love interacting with beautiful, well-made things, maybe this is the choice for you. Moleskine is the most well-known of the prestige notebooks, but it’s not the only one. Paperblanks offers beautifully designed notebooks that are almost works of art in themselves. What kind of pen is worthy of those notebooks? Perhaps a Montblanc or a Conway Stewart.

15. PDA software with its desktop counterpart. For example, Palm devices like the Treo come with Palm Desktop. Makes sync ultra-easy. But you might give up some features you want in your task manager in exchange for ease of synchronization.

16. Desktop to do list app for your PC or Mac. To Do X for Mac allows you to print in many different ways–great if you like to enter and manage tasks online, but print and carry lists with you. There are, of course, lots of shareware options for Windows and Mac including To-do List 2.2.1 for Windows.

17. Or create your own desktop app. If you’re at all familiar with Microsoft Access or another desktop database management program, it’d be easy to create a table of tasks with whatever attributes you want: due date, category, project, and so forth.

18. Outliner software, web or desktop-based. Good if you are managing multiple projects but don’t want the overhead or extra complexity of a project management app with Gantt and PERT charts. Buy a Mac, and you’ll get OmniOutliner. If you’re an RSS geek, you might like to use Dave Winer’s OPML Editor. On Windows, you might try NoteMap. Want to combine your outliner with a mobile PDA? Try the Carson method, one geek’s method that uses OmniOutliner with the Hipster PDA.

19. Online wiki. Free wiki services like PBwiki and Wikispaces make it easy to create, edit, and share web pages. Some wiki platforms support interaction beyond simple creation and editing of pages. Have you heard of Monkey GTD, a “GTD inspired task manager” that uses TiddlyWiki plus plugins to implement getting things done? Here’s Monkey GTD in action.

20. A piece of paper with a pen. Easiest and cheapest. I use looseleaf paper, one page per “context” (at computer, at home, errands, to call) and staple them together. It’s completely mobile, just fold and go, and I love scribbling out items when I complete them.

What tools do you use to manage your to dos? And how do you combine them into an overall system?