Hi,
Gears uses Windows Mobile's 'GPS Intermediate Driver' to access the
GPS, so you may need to set this up. There are instructions at
http://blogs.msdn.com/windowsmobile/archive/2006/06/07/620387.aspx.
Note that you may need to edit the registry to enable the required
settings panel.
Also, make sure that PositionOptions.enableHighAccuracy is set to true
to instruct Gears to use the GPS if present.
Steve