Facebook IM is a freeware Windows Phone application that brings the facebook chat on to your Pocket PC.
It requires an active internet connection on your device. No 3rd party registration is needed, this app connected directly to the Facebook website.
Installation:
Copy the CAB file to your device, and execute.
Video Preview of Facebook IM
Update Description:
V2.1 (13/3/2009)
* improved User Interface
* better fit for QVGA (smaller images)
* automatic thumbnails cache cleaner
* facebook new notifications indicator
* unread inbox messages indicator
* fixed random messages not arriving
* fixed freezing problem upon connecting
* added facebook phonebook link (on the Web Menu)
* added full status and status time on chat window
* improved touch scroll