I ported my vonage number to a cell phone then ported to google voice. ($20 a hop). Our vonage line was ringing to our cell phones anyway ( and we would often call back from our cell phones anyway)
If you want the outgoing call to come FROM your gv number, use the web, google chrome extension, android or iPhone apps (or web app). Hint, if you have friends/family on your mobile plan, put your gv number on your plan and set gv to always ring you with your gv number (with call presentation on), then all calls coming inbound come from your gv number and are free calls. /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
