Google is giving out more Google Voice invitations on a first ask, first serve basis.  By now they probably have hundreds of thousands of requests, so don't delay if you haven't asked for one yet.

Today I discovered another great feature.  If I'm coming back from work while on a call on my cell phone, I can hit the *-button and GV will ring my house phone.  Answering it will transfer the call and I can save my cell-minutes.  Also I discovered that GV can save time touch typing on my iPhone:  When logged onto GV, you can easily send SMS txt messages free to anyone.  Just type in the name-if they're on your contact list, their number will pop up-and message away.