These are some of my favorite Sailor Moon sites. They have other anime as well as Sailor Moon.
grep* SailorMoon- has just about everything including tons of pics, fan art, and multimedia.
projectanime.com- has a couple of fun things to do, including postcards
Tuxedomask dot Com- loads of stuff to do on this site. well-compiled and updated frequently.
sailormoon.net- need to buy stuff? sailormoon.net can hook you up with loads of Sailor Moon paraphanalia
You Know You Watch Too Much Sailor Moon When- long list of funny things. Visit this page if you want a good laugh
Karl's Unnecessarily Long Sailor Moon Link List- has so many links for everything Sailor Moon
Chibi Selena-chan's Archive of Sailor Moon Manga- manga archives
Fritter's Sailor Moon Indulgence- great site. Has so much stuff that indulgence is an understatement.
Quentin's Sailor Moon Midi Center- speaks for its self. has lotsa midis
DARK JEDI's Sailor Moon Page- pretty cool page. there are a couple of neat things to do.