www.soccerplus.net http://www.soccerplus.net/usa04home.htm http://www.soccerplus.net/usa04blue.htm I bought personalized Red 00/01, Blue 02/03, and White 02/03 ones through them and was generally happy with the quality -- the letters and numbers were the official style/font. I haven't purchased a new one yet, so can't speak for the current names/numbers, but the numbers and names at the links above look right, too. and The Onion Bag dot com also carries them with the official names/numbers.
I got a Mathis away 02 WC jersey from Soccerplus ... top shelf stuff I've been in Onion Bag shop and seen new jerseys and numbers...they re also high quality Eurosport also has a few of what they call "Hero Jerseys" if you get their catalogue.