Penny Arcade Expo will indeed be launching a third event this year but this one will be a little different. It's called PAX Dev and it will be strickly for game developers for the purpose of "elevating the art and creating place to share, debate and learn." Not even the press will be able to attend this event.
The show, which is aiming for a low 750-ish attendance number, will be held on August 24 and 25 at the Sheraton Seattle Hotel, just before the massive PAX Prime 2011 event is held in the same city. If you want to go and are a real game developer you can do so for $249 for both days or $129 if you are a student taking game development courses.