Everything originally comes from time and then returns back to it again. Such is the way of the universe...

Lycentia's SM Graphics~ A fantastic place for layouts, buttons, and sprites.
Tatakau~ This place has many game sprites for editing.
Sailormoon Channel~ If you feel like poking around in Japanese, this is the official BSSM web site.
Gallery of Moonlight~ This is one of my favorite resources for Sailor Moon art.
Sailormusic.net~ If you are looking for any Sailor Moon music, this is the place to find it.
Manga Style~ This is the best place I know for SM artbook scans.
Serenitatis~ Yet another fantastic collection of SM pictures.
Blood Types~ When creating a character, this is a great resource.
The Oracle~ A fantastic resource (with some biases) on Sailor Moon information.
The Shyguy Kingdom~ Yet another great collection of game sprites.