https://www-304.ibm.com/support/docview.wss?uid=swg21470120

Following Nokia’s February 11, 2011 announcement of their plan for a partnership with Microsoft and Windows Phone as their primary smartphone platform, the longtime IBM and Nokia relationship will continue. The IBM 2011 strategy for the Symbian platform remains unchanged. IBM will continue to support its mobile products on Nokia Symbian devices that are in market today and intends to add support later this year for Nokia Symbian^3 devices based on customer demand.
IBM Collaboration Solutions organization has no plans for Windows Phone support at this time. The IBM Collaboration Solutions team will continue to watch market trends and listen to its customers as the prerequisite indicators for forming plans relative to Windows Phone support.