The GPS hardware page.
Software found elsewhere (location services - see SDK.)
The Palm Pre has a built-in hardware GPS for location services.
There is some misleading information out there, because the initial tear-downs didn't spot a separate GPS chip it was earlier thought the Palm Pre didn't have a GPS and thus must rely on cell phone tower location.
This wasn't entirely accurate - the Palm Pre does indeed have integrated GPS hardware, and uses GPS if it's turned on (enabled.)
If the GPS is on, GPS hardware will be used.
If the GPS is turned off in Location Services, the Palm Pre will fallback on cell tower location.
The GPS hardware is physically located on the Comm board as part of the OMAP3 chipset (PDF file),it's integrated into the NL55xx Bluetooth chip.
so, this means the chip might be marked "NL5500" or similar and will be TI brand
Palm announced at CES the Pre uses the TI OMAP 3430 as an applications processor. Here is the Omap 3 bulletin from TI - PDF file. Here is the mainARM chipset detail from TI - PDF file. Rapid Repair shows the comm board in Step6 here. (photo.)
There are Mojo methods detailed in the SDK under Location Services (and so, no need to also detail them here.)