I am a 2Lt in the Army Reserve. I made initial contact with my recruiter in October of 2007. I completed my "packet", obtained the required LOR's, completed the CV, obtained copies of all my my various licenses and certs, diplomas, transcripts etc, and submitted it all in November of 07. I obtained the "physical" in December of 07. I was "boarded" in May of 08 and accepted in the beginning of June of 08. I was Commissioned on July 1st of 08. As of today, December 19th 2008, I am still awaiting orders to report to my TPU. You are not "official" until you receive orders.
Fair warning: THIS IS BY NO MEANS A FAST PROCESS. You will wait, wait and wait some more. Just go in knowing that the wheels of Army bureaucracy turn VERY slowly.
There has been a prevailing theme here: Hurry up and wait.
I realize that my timeline is the exception to the rule. Generally speaking, the time it takes from initial contact with your recruiter to receiveing your orders is averaging around 8-10 months. It could be faster, it could be slower. It depends on a number of factors. Some are in your sphere of infuence, some are not.