[varunb007]

Changing the following registry value seemed to solve all of my problems:

[HKEY_LOCAL_MACHINE\Comm\ConnMgr\Providers\{7C4B7A3 8-5FF7-4bc1-80F6-5DA7870BB1AA}\Connections\Phone as Modem]
"Enabled"=dword:00000000"

Change the value to 0, and soft reset.

It appears that the GPS, by default, makes use of the "Phone as Modem" data connection to take advantage of aGPS, but if a "Sprint PCS" data connection is already active, the GPS doesn't swap connection methods and ultimately hangs. This problem is exacerbated if you have Push services or other data connections running.