Don't know about the net, But....
There are two videotapes I know of that help: Grandmaster Uechi performs kata (forget exact title) and highlights from the 64-65 tour. The former show's master uechi doing sanchin, seisan, kanchin, and sanseiryu and is invaluable. The latter shows students doing all kata. Both available from this site. At least some of the other videos I've seen are not worth viewing, but can't comment on all.
There are kata photos and descriptions in Sensei Mattson's Uechi-Ryu Karate Do and others, including, I think, Allan Dollar's text.
I had students complain there aren't any good written kata descriptions they could find on the net and in a few books they loked in so I wrote some of my own:
http://scs.student.virginia.edu/~uechi/style.html
Of course the most important thing is having an instructor. Someone who is at least familiar with the kata who can give you some tuneups. A lot of my learning in Uechi has been selfguided with periodic checkups by Sensei Glasheen because of time and distance constraints, and that has worked out well. But the tuneups are pretty important. The writeups on my site, for instance, are supposed to help students master sequence on their own so they can get valuable pointers in class and not waste all the class time on learning the sequence. They can't substitute for class. I've seen proof of this.
Learning all the kata at once or rapidly doesn't do a lot of good either. There's a good progression from sanchin to seisan to sanseiryu that should be preserved and tackling all the bridge kata at once negates the Uechi emphasis on quality over quantity.
Good luck and have fun training!