Two ways to determine what your iPad is equipped with from a network connection perspective.  Visual - the 3G model has a black plastic band at the top of the back surface.  The WIFI only model does not, it's all aluminum.  Google Images has pictures of both.  Model Number - go to Settings > General > About > Model.  Type the model number into your favorite search engine and hit enter.  Most of the links will show the iPad's key distinguishing features.  For example my model is MC984LL/A which is a 64GB, WIFI + AT&T 3G, White, 2nd Gen iPad.

Only the 3G models have a built in GPS receiver which operates independently from the 3G receiver, however the 3G and WIFI signals are used to augment the GPS location accuracy.  Therefore you don't need to activate the 3G network for the GPS to work.  Again, there is no GPS receiver on the WIFI only models.

Sent from the BeachPad