sproutliner is a free outliner on the Web that works surprisingly well. I wouldn't use it for really private stuff (anyone can see it if they know the name you used for the project), but it's perfect for a simple to-do list. It's then accessable from anywhere with an Internet connection and browser.
This is yet another piece in my project to free myself from any particular computer. I can now get my email and contacts list, photos, blogs I read and Web bookmarks from any computer that's connected to the Internet, running any decent Web browser.