Sorry, I thought the comparison to PocketDay would be enough....
Pocketbreeze is an app that runs at startup to combine your calendar and to-do list into one.
http://www.sbsh.net/products/pocketbreeze/
By far the best thing I ever got for my Axim, and it would go a loooooong way toward making the BB an easy replacement for it. (I'm struggling with making the change from Windows Mobile to Blackberry)