HTC Desire User Manual page 253

Changing privacy settings
You have control over how and when you can be found by your
friends. Only the last location sent to Latitude is stored with your
Google Account. If you turn off Latitude or are hiding, no location is
stored.
1.
In Google Maps, press MENU, and then tap Latitude.
2. Tap your own name, and then tap Edit privacy settings.
3. Set the following options to your preferences:
Detect your location
Let Latitude detect and update your location as you move. The
update frequency is determined by several factors, such as how
recently your location has changed.
Set your location
Choose from several options to manually select your location.
Hide your location
Hide your location from all your friends.
Turn off Latitude
Disable Latitude and stop sharing your location or status. You
can always join Latitude again.
Maps and location