I setup a free account with Backpack today and I am very impressed. It is an simple and elegant online tool that can be used for just about anything you need to write down or remember. This service is one of many great offerings from 37signals, the makers of Basecamp, Ta-da List, and Ruby on Rails.
I am using it for my “to do” lists, notes, and calendar right now, but can see using it for much more in the future. One of the indispensible features is being able to automatically have Backpack send email or text message reminders for my appointments. Great for people who bounce between a few computers or aren’t always at a computer and get text messages on their cell phone.
Sign up for an account now (shameless affiliate link below). You won’t be disappointed.