Install the AppBrain app, it'll sync all the apps you have on your phone with the app, and also allow you to sync the list with appbrain.com
You can then delete apps from the appbrain app, or from appbrain.com (the app syncs the list of apps to be deleted back from the website).
Simplest way to do it that I've found, and it is also the easiest way of getting apps onto the phone from a computer (search on appbrain.com, sync to appbrain app, done)