All you need is at least 3 satellites in mun orbit and a series of ground stations. Just make it so all three satellites can see each other, and the ground stations can see at least one satellite.
You can try out the WIP probe game here http://dl.dropbox.com/u/575558/Probe.zip (Thanks to HarvesteR, C7 and Iskierka for helping me with the math behind the gravity, arguably the most important part of it)
When I get it to a working state, I\'m going to upload the whole project - it should be helpful for this community project of yours. If anyone needs any models or textures, I\'ll be happy to help.