Tiny Tile Mosaics- Offers the smallest ceramic mosaic tiles produced in the world! Also a great source for jewelry blanks for mosaic jewelry!
MASGO- My favorite of mosaic and stained glass forums! A wonderful community of fun and helpful folks.
SAMA- The Society of American Mosaic Artists. A wonderful orginization and reference for the art of mosaics!
Mosaic Rocks! - An eye popping assortment of natural elements made available by some some of the biggest supporters of the mosaic arts.