(Can't post links...change "httx" to "http" to get this to work.)
If it does what it's advertised to do, this is a HUGE deal. It should solve any problems people are anticipating with the App store, installing multiple apps, etc.
I hated it. It only allows you to put the installation files on the card. Then every time you want to use a program you have to actually install it to the phone from the SD card, use it, and then uninstall it again. I found it complicated and too much work! RIM just needs to fix the OS so we can access more memory if necessary. The phone has a lot of memory on board that most people aren't even using.