Ok lets try again: Have you configured any voip on your n900? If yes, did that voip provider give you a phone number? If not, then first you need to get a number for your voip service. Once you have that, open a browser on your desktop machine, log into Google Voice, click the settings icon (a gearwheel), click "Voice Settings". On the Phones tab, there should be a link that says "Add another phone". Click it. Enter the phone number of your voip service. Follow the prompts and save. Now, back on your n900, close DC if it's open, and open it again. Go to the callbacks settings. You should now see the number that you entered into the Google Voice settings. Select it. Make a test call. ??? Profit!