[pkjh]

I was told PB has a GPS built-in,but why I couldn't find anywhere on the APPS.

[daphne]

It does have internal GPS but it's not listed as an app. There are some apps that use the internal GPS however like Bing.

[Boight]

What is it you want GPS for? There's a wide selection of apps that use it.
If you can be somewhat specific then we can offer experience.