Check out the list of the best sites I have found:
Probably the best site... lots of pictures, his life besides tennis etc...
INTERNATIONAL SAMPRAS FAN CLUB
A dutch fan club.
The official site. Just have a look!
US Tennis Magazine
American magazine about tennis!
JOE'S ATP TOUR STATISTICS
A web site really well documented, with a lot of statistics about the most famous players since 1991!
This list must grow. You can help me...