You can get it on both devices. I don't remember if there is a 'launcher' that comes with the Pearl, but I know there is one that comes with the Curve (basically it's an icon you click on to install AIM - you don't have to search for a link to install the software).
This may help you make up your mind, too:
Sprint BlackBerry Comparison - 8830, 8130, 8330 | BlackBerryNews.com
If you do decide to go with the Pearl, you might want to read this, too:
SureType - Learn To Love It | BlackBerryNews.com