More than 15 people have contacted me looking to receive an invitation to Google Voice, unfortunately Google has decided not to include an invite quota for their invitees as they did GMail back in the day.  Hope this clears up that question :: here are a few reasons why I believe Google has appeared to cease sending invitations to the public at large :

1. PSTN termination is expensive – and as much cash as Google has, I can’t imagine it being extremely lucrative at this point with free North American dialing.
2. Google purchased a block of 1,000,000 DID’s (phone numbers) which very well could be their “beta pool”.  I could be wrong but they may keep their testers to a “small” group until they figure out if they should continue (turn a profit from the service).
3. There have been issues with SIP trunking, apparently they dropped it quickly when some clever folks discovered Google was using shockingly weak passwords.  This may be something they want to clear up before inviting more people.

As soon as I heard peoples patience was wearing thin, I decided I would sign up for another account with my other GMail address (seeing as I received my first invite within two days).  It has now been a month with no response – so don’t fret, you are not the only one.  As far as I can tell there doesn’t appear to be any pattern to their invite protocol, I think in the beginning it was really all about timing.

As frustrated as you may be eventually you will get your invite – lets hope you don’t have to wait another two months… Good luck to you all and in the meantime read my first impressions.