For outgoing calls you can use GrooVe IP or if you didn't have a good data connection you could install and use the Google Voice android app. The Google Voice app will use your cell phone minutes but the outgoing caller id will be your Google Voice number.
Perfect! I wasn't sure if I could use GV over a cell signal. So basically, when I'm home/wifi, I should call with Groove IP and when I'm out/no wifi I should call with GV right?
Groove Forwarder sounds PERFECT for what I need. What do you mean by needing a data connection though? I have a cell plan but there is no 'data' on it, just minutes. Will it still know to switch? I'm going to go ahead and give it a try! Thanks so much! GV is looking more and more attractive to me now with the one number thing.