Nortel (NYSE:NT) and Research in Motion (Nasdaq:RIMM) signed an agreement under which BlackBerry devices will have added VoIP capabilities via Wi-Fi.  This will require a tight integration between RIM's BlackBerry enterprise platform and Nortel's CSE 5100 multimedia server.  As announced at VoiceCon 2005, the first model to incorporate this feature will be the BlackBerry 7270, albeit it will be a VoIP-only device (to be used not only in enterprises, but also over public WLAN hotsports).  However, the future is really all about seamless roaming, so the market is IMHO ready for a dual mode BlackBerry that could function in 2.5/3G mode or in Wi-Fi/WLAN mode. 

Note: RIM also signed a similar partnership deal with 3Com, which will use its own IP PBX and WLAN switch (licensed from Trapeze).