[EVO 4G Q&A, Help & Troubleshooting] drmacinyasha:
Hold up, hold up, hold up.

Mmmkay, here's what you do.

1) Go get a Google Voice account with a local number. Get that all setup so it'll ring your cellphone (trust me, just stick with this).

2) Head on over to Sipgate.com and sign up for a free Sipgate One account. When it asks for a phone number to verify that you're not a bot registering, give it your real cellphone number. Don't worry if you can't get a "local" number and only wind up with something in California (don't worry, just follow the instructions).

3) Download and install Sipdroid on your EVO. Make sure to set "Preferred Call Type" to "Phone" (otherwise Sipdroid will always take over for all outbound calls. This is bad when you get back in the country, and because Sipdroid doesn't play well with Sipgate for outbound calls, which also cost money on Sipgate). For the SIP Account settings, grab these off your control panel on Sipgate's website (Go to Settings, then on the right-hand side, you'll see "SIP Credentials". Click that) and use the SIP-ID and SIP-Password for the Authorization Username and Password fields in Sipdroid, appropriately. Use "sipgate.com" for Server or Proxy and Domain. Leave Username, Port, and Protocol as-is. Next, go to the Call Options menu in Sipdroid, and enable "Use WLAN", "Use 3G", and "Use EDGE" (Yes, there's no EDGE on CDMA, but it's just to prevent issues). While you're out of the country, you can disable "Use 3G' and "Use EDGE" to force all calls to be WiFi-only.

4) In Sipgate's settings, go to the Forwarding section, and clear out all of the rules (We don't want Sipgate to handle voicemail, as Google Voice will be taking care of that).

5) Add your Sipgate number to Google Voice's list of phones. Make sure to mark it as a landline (not a cellphone) and that you have Sipdroid open and connected when you go to do the verification. Congratulations, you're all set up!

Now, when you leave the country, open up GV online, disable your cellphone's number (your Sprint number, not your Sipgate number) as an available phone. Set Sipdroid to only use WLAN, and I'd recommend putting your phone in Airplane mode with just WiFi turned on. Now people can call and text your Google Voice number (you can install the Google Voice app on your EVO to manage voicemails and texts, and when you get back in the country, to handle calls, too!). To make calls, that's a little more tricky. You have to open up the Google Voice site in a full browser (you can try setting your UAString and all that to Desktop on your EVO's browser, but it doesn't work too well), and then click the "Call" button in the top-left, and select your Sipgate number as the phone to call with, type in the phone number to call, and hit Connect.

Now, the beauty of it all: How GV works is when you have an incoming call, they just forward the call to your number. When you make an outgoing call, GV calls you, then establishes a conference call between you and the destination. As soon as that happens, GV "leaves" the conference call, just leaving you and the destination connected with each other. This works perfectly, as Sipgate One allows for unlimited, free, inbound calls. In addition to all this, you can use a computer with a headset, and the new Gmail to call people directly from the Gmail webpage. Nifty, eh?