In 2007, Google acquired GrandCentral and just re-launched it as Google Voice. The service, which gives users an incoming number that can be forwarded to as many as six phones, allows you to screen calls and record them, and transcribes your voice mail into e-mail and text messages. I spoke with GrandCentral co-founder and now Google executive Craig Walker about the service's features as well privacy issues and whether Google will ever make any money from it.