Is it possible to use VoIP over gprs from an Android phone? Either using a SIP client or Skype?

Possible Duplicate: How can I receive phone calls through WiFi on an Android phone? I have an unlocked Nexus One. I barely use the voice function, mostly just use data. However, I'd like to have the voice function just in case. Is it possible to use something else (possibly VOIPish) to replace the voice plan that I am currently paying? Perhaps Skype, or Google Voice or something else. Has anyone had an experience with this? Thanks

Well Fring is blocked. I'm located in China. I neeeeed to make free skype calls to my family around the world. Skype Lite is not an option, has anybody cracked this cookie?

I see that Skype offers an Android version, but it only works on Verizon? Fring used to connect to Skype, but now it looks like they don't. Is there no Skype client for Android?