Just getting started...comments/advice appreciated.
6/14/07: Received an email today from one of my undergrad institutions stating that my transcript had been sent to AMCAS yesterday. Seeing as how I made that request over a week ago, I'm not too impressed.
 Infatum est!
On a brighter note, I've completed AMCAS and my list of schools is finalized (see above). 
6/29/07: AMCAS received my other transcript today! WOOHOO! Now, about that verification...
7/3/07: Received U. Chicago and Wash U. secondaries today. Kind of surprising, considering I'm not even AMCAS verified yet.
7/10/07: AMCAS Verification! Received UNC and Tri-I secondaries as well. 
8/25/07: Texas Southwestern interview invite
9/10/07: Vanderbilt interview invite
9/22/07: So, I can't believe I'm saying this, but I've now completed my first MSTP interview (UTSW)! It was a little surreal, considering that this is one of those life moments that I've been thinking about for around a decade, but I managed okay. All of my interviewers were laid back, which helped big-time, and none of my nightmare scenarios (freeze-up response to a question, weird body sounds, Turets-like profanity, etc.) became reality. While I probably could have done a better job explaining my research, I'm beginning to see the trend of my worst fears never coming to fruition...perhaps I worry a bit too much :-) Bring on the STRESS INTERVIEW, BIOTCHES!!! I'M READY!!!
9/22/07: Case Western interview invite: rock on Cleveland!
10/11/07: UW invite
11/11/07: This process takes too long. Please, MSTP application gods, can I just get ONE token acceptance this week?! Is an alleviation, before Thanksgiving, of the several mental disorders (see below) that I've presented since starting to fill out AMCAS too much to ask for? ...'all I want for Christmas is an M-S-T-P...'
(11/11/07) My next publication: 'A Downward Spiral': or, 'Tracking the general psychological profile of an MD/PhD applicant.' Findings would include an onset of obsessive compulsive disorder during MCAT score release month, multiple personality disorder during the first interview weekend, post-traumatic stress disorder AFTER the first interview weekend, amnesia (specific to science-related memories/knowledge) during committee interviews, and transient Tourette's syndrome immediately following each MSTP rejection. Mental reaction to MSTP acceptance is (hopefully) forthcoming. 
(11,12/07) WashU, U. Chicago and Stanford interviews!
(12/12/07) Scored the UCSF/Hopkins/Mayo rejection trifecta today! UCSF is the only one of the three I'm really bummed about, though. But I went 1/2 on Bay Area interviews, so I guess I can't complain. 
(3/15/08) U. Chicago revisit = AMAZING. This place is an intellectual cauldron with absolute creme de la creme research in my interest areas (immunology/micro with a structural/biochem component). Plus, Pritzker is a really special place to learn medicine. A week ago I was 90% in favor of UW, but now my UW revisit will be of utmost importance. This decision is getting really tough, but it's a great dilemma to be in. 
(4/14/08) The U. Washington revisit was convincing; I'm going to SEATTLE!!!
No applications have been submitted yet during this cycle.