This comes from a reader who recently got a BlackBerry Pearl 8130 from Telus. They had the Facebook application installed on their BlackBerry and were able to send messages, pokes and wall posts however not able to read them. The Facebook mobile alerts were enabled however still no luck.
The simple solution: In order to read new messages or wall posts in the Facebook application you have to have the email account you receive notifications setup on your BlackBerry. The good news is if your a Facebook addict you won't get tons of emails on that account because Facebook automatically stops sending them to you device when you get a notifications on the application.