Simon at BBcool just tipped me off to a new Facebook application that will be coming out for BlackBerry devices. This is an application designed by RIM so it should integrate nicely with your BlackBerry. It seems that RIM is really serious about penetrating the consumer market. This is going to give the T-Mobile Sidekick a run for its money. Check out the OTA download link below to get on Facebook today 
You can read more from the Reuters article on the new application:
The application will let users receive Facebook notifications and messages automatically and scroll through them quickly, just like the e-mail service for which the BlackBerry is already well known. Users can also read and compose messages even while off line, RIM said.
The feature that lets users upload photos to Facebook will also be integrated with the BlackBerry’s camera and photo management software, RIM said.
Ben Eng Not Registered
Posted: October 25, 2007 at 11:49 AM EST
It looks like the Blackberry 7105t does not meet the system requirements to run the facebook app. Boo!
BerryReview ( View Profile) Senior admin - Posts: 5298
Posted: October 25, 2007 at 1:59 PM EST
Sorry to hear that Ben.
I just found this:
http://na.blackberry.com/eng/services/internet/facebook/download.jsp#tab_tab_requirements
It says the requirements are 64MB Berry with os 4.2+