Yes, it’s a logical step for jailbreakers when facing this kind of case. GV Mobile developer Sean Kovacs has ported the Voice client over to Cydia for free –although donations are gladly accepted– following Apple rejection on all Google Voice-enabled applications and Google’s official Google Voice application.
Please note that Google Voice is not a VOIP service. Basically, it’s a service that lets you manage a free phone number that Google gives you. Since the app relies on the Internet connection (3G, EDGE, Wifi, etc), so you still need an actual phone plan.
The GV Mobile features including:
- Dial numbers (domestic for free and international at a variable rate) via the iPhone’s address book or typing in on the keypad
- Send SMS messages
- Retrieve and delete recent call history
- Playback and delete voicemails
- Take calls from different phones other than your iPhone
- Add, delete, enable, or disable the phones that Google Voice forwards calls to
Google Voice is currently in beta and invite only.