For the last few years I used Remember The Milk (RTM) to track my personal to-do lists, but found the annual subscription a little too high. So I looked for an alternative and Toodledo (http://www.toodledo.com/) is it.
Firstly, it’s a crap name, it sounds like some kids game, but putting that aside it’s a neat service and the key part is there’s app that sync to the web service for the iPad, Android devices and Blackberry too.
I just bought Taskjot (http://www.taskjot.com/) for my Blackberry to get my to-do’s on it and it works a treat, so all the pieces are there for me to run and have access to all my up to date actions on pretty much any device.