I keep a little directory of Phantasy Star sites on my web page. Every few months I do a sweep to purge dead sites. Along the way I revisit all the long defunct ones.. ones that haven't been updated in years but are still out on the internets. Here are a few interesting ones:
Make sure you have a pop-up blocker and Java disabled before visiting any of these - consider yourself warned
Wizardmage's Phantasy Star Kingdom - A PSIV site that never really did much, has some good maps though.
Rysel Online - A page dedicated to the town of Rysel from PSIII. Whatever floats your boat I guess.
Alisa III - I exchanged emails with the owner of this site years ago. He was taking on the ambitious project of creating overworld maps for PSIII and wanted to know if I could share some source images. Since I never tried to create overworld maps I couldn't. However, he managed to create a few.
Phantasy Star Quiz - Javascript quizzes for the original four games.
Any others out there?