You mean the pushposters.com link (Posters, Clothes, 2003 Calendar, and Pins!)? I didn't see it on any of the three pages... I've been looking for this shirt since the PopMart tour, when (like an idiot) I didn't get one; I got a different shirt and it's been impossible to find. I heard the shirts were discontinued due to copyright/trademark problems with the company that makes Pop Tarts, so I'd pretty much given up on finding one. If there's a way to get one, though, I'd be willing to spend ridiculous amounts of money; I'd just have to save up first.
Try Ebay. I just got one of those "babydoll" Poptart shirts last week, and am so in love with it! A seller in England was selling them, and I did the "buy it now" option so I was sure I could get one, rather than losing the auction.