When I cater BBQ events, these are the two homemade sauce recipes I have perfected. One is a more traditional style sweet and smoky BBQ sauce and one is a take on a tangy South Carolina style sauce, which is amazing on pulled pork and chicken. They are both posted here:
http://drewcooks.com/blog/2008/how-to-video-great-bbq-ribs-on-the-smallest-bbqs/