On my old iPhone 3gs, once jailbroken you could install an app called VOIPover3g and trick your phone into thinking it was on wifi even if you were only on 3g so you could overcome the restrictions on certain apps like skype (only lets you make calls over wifi) and youtube (better video quality on wifi)

Well, Vonage just came out with a great app for free domestic calls with GREAT call quality, but it only works over WiFi.

How can we trick the N1 into thinking its on WiFi even if its on 3g?