Research In Motion has officially published documentation for the upcoming BIS 3.1 (expected next month), and it largely confirms what we’ve been expecting. The major hitting points are:

• Two-way contact (address book) sync with Yahoo! and Windows Live Hotmail and Sync ML (ALT-N)  (Note: I was unable to find any mention of Snyc ML, but I may have just missed it.)
• Ability to share credentials on the device for an overall easier Windows Live experience (Always nice for the Windows Live users out there.)
• User able to self delete BIS account (added security)

While not game changing, these are nice, incremental upgrades to the BIS platform (especially the added Yahoo! sync and the self-delete option) that should continue to enhance its functionality. The next BIS is expected sometime in October, and is rumored to be adding calendar sync with Yahoo! and Google, along with a small-business oriented management console. For full documentation regarding the 3.1 release, head on over to the BlackBerry documentation site (and then come back and let us know what you think!).