I've been using Google Voice for 5 years now and have yet to receive a single email spam, call, or text message sent my way.

Anyway, nice thread.

If there's anything else to add, I guess I could also mention this site for when you're making calls from home.

http://www.audiocheck.net/audiocheck_dtmf.php

I have each of my contacts saved as a .wav file and simply play one of them through mediaplayer when calling.

Just hold the tablet near the speaker phone.

They should each be 76 kb in size because you need a few extra sound delays when it goes through the Google Voice menu system otherwise it won't work correctly.

Cheers.