[Priest]

I've been using Loudtalks for a while. It's a great PTT app, even allows you to listen to past messages. And yes, it's FREE.

As far as how it works, you basically add people to your buddy list and then like most IM's it shows who is online/offline, etc. You choose the username and then can push to talk with them.

@jpwhre, I've encountered the same issue with the add request not showing up. Usually if he adds you, and you add him, then it syncs up. Try that...