"A few weeks ago we released Google Maps for mobile with Transit directions for BlackBerry and Java-based handsets. Now, with the release of version 2.2 of the application for Symbian S60 (3rd edition or later) and Windows Mobile (2005 or later), we're happy to say that Transit directions will be available to a bunch more smartphone users around the world."
Google Maps 2.2 is now available for Windows Mobile. It adds Transit directions for over 50 worldwide cities/regions, star ratings for businesses, faster search, and user-generated content. Simply point your mobile browser to google.com/gmm to download.