I've had my tour since Monday and I have not been able to access my AIM account. It would go to sign in and it would say Service not available for this phone. I've tried wiping it and everything. Finally it hit me. Why don't I just have RIM send me an email with the AIM download link? Well guess what it works like a charm. Here's the link if you need it. BlackBerry - AIM for BlackBerry - AIM for BlackBerry Smartphones - AOL Instant Messenger
Enjoy fellow Tour users.