A quick search with Gooooggllee turned up a few interesting items. In particular here is a link to a schematic for a multi-channel light dimmer project someone did that has micrcontroller based operation with an integral zero crossing detector (although I would have implemented the zero crossing detection on a secondary winding of the transformer).

http://www.schematicsforfree.com/lights/Mi...Dimmer.pdf

Michael Karas