I don't know anything about a browser-based AIM Express, but I'm running the new Blackberry navite app from T-Mobile's software upgrade site. It's not specifically for my model but it works perfectly. No OTA download, but you can download it to your pc and use the desktop installer to load it onto your 'berry. Here's where I found it: http://www.t-mobileapps.com/download...m?selDevice=14
It's a Wireless Village client configured for Tmobile's Wireless Village server/s. It uses SMS msgs with various codes to communicate with the WV server.