From the Press Release...
"This announcement with Nokia further demonstrates the importance consumers and businesses place on accessing Exchange Server data from mobile devices in addition to traditional desktop clients."
Terry Myerson, Corporate Vice President, Exchange Server, Microsoft Corp."The Nokia-Microsoft collaboration to bring corporate mobile email to businesses and mobile professionals is truly unbeatable. No other device manufacturer provides the wide range of devices that we have which immediately mobilize the hundreds of millions of email accounts from Microsoft Exchange."
Anssi Vanjoki, Executive Vice President, Markets, Nokia.
The S60 blog discusses this more, and the full press release is here.
Here is Nokia's Petri Asunmaa discussing the news (via Nokia Conversations):