Here are a couple of articles I found a while ago -
http://findarticles.com/p/articles/m..._98124194/pg_1
http://www.tacticoolproducts.com/bulletcasting/
http://www.freewebs.com/castbullets/
Also, check out the Ammosmith channel on YouTube, do a search on his channel for "casting", lots of good videos.
http://uk.youtube.com/user/ammosmith