As shown in this video, the app works quite well and is rich in functionality. It gives you the ability to view photos, track your news feed, send messages, view friends' profiles, and even dial or SMS your friends directly from the call tab.
Facebook for Windows Mobile works on all screen resolutions, and is rumored to work on non-touchscreen devices as well. If you want it, grab the CAB from XDA. The app won't work if you install it onto the storage card, so install it to the device.