Left 4 Dead Map Pack?

Unless I've been out of the loop, can some one tell me when they're expected to release the new map pack(Crash Course) for Left 4 Dead? I've got a pc and Left 4 Dead is played a good amount in our home and was just asking here since I had a few issues finding the date.. THANK YOU!

I looked around the internet for a minute and several places just say this September. It shouldn't be long.

Crash Course should be out by the end of the month.