Fujitsu Siemens have announced the Pocket Loox N520 device which has integrated GPS, Wifi and Windows Mobile 5. 

Fujitsu Siemens LOOX N520 GPS Pocket PC + WiFi

 

You can pre-order on Expansys - http://www.expansys.com/product.asp?code=126748

There is also a good preview on Mobile Review - http://www.mobile-review.com/pda/review/fs-loox-n520-en.shtml