Is there an application to emulate I'm in a different location? I'm trying to test an iPhone application and I need to simulate I'm in a different location. I was wondering if there is an application out there in the market that let's me write some longitude and latitude so my app can read that location instead of the actual GPS in the phone.

I don't have access to the code or an iPhone emulator, so I need to test this from the device itself. 

Any possible way to do this?
There's no way to do this in the App Store. Unfortunately, you'll need to use Xcode and the iPhone Simulator to do this. This Stack Overflow answer describes how to do this. 

Edit: Yes, it is possible using a Cydia program, called LocationHolic.