fake gps for android running in virtual-box

Question

I am trying to virtualize GPS device in android running in virtual-box. I want to facilitate an app running in android to use the gps device or get a fake gps location some how. I have started looking at the android emulator source code but meanwhile, any one has any good place to start with.

[UPDATE]

To make it a bit more clear, the whole application stack would be some thing like:

Android app (with gps functionality) to be tested ----> (developed by end user)

Android virtual machine ----> (Guest OS)

virtual box ----> 

Microsoft Windows ---> Host OS 

Now, Ideally I would like to have my application (like adb or ddms) running in Windows from where the user can set some coordinate values for gps device (in absence of actual GPS, else virtualize the existing GPS) . These coordinates would be available to the android app. Basically, this is same as providing the functionality of existing android emulator (using ddms) through virtual-box running an android image.

I am NOT running android emulator and I am not using eclipse. :( [UPDATE ENDS]

Thanks, Vikram.