AMP help.......PLEASE!!

I was wondering what size/kind of amp i should get to push my 2 12" type r SWR-1242D 500rms and how i would go about hooking them up without blowing the subs(i know all the basics like running the wires its the amp settings im worried about).I'm going to build my own box, and the only thing im having trouble understanding is the gain and anything else that may cause me to blow the subs through the amp. What kind of head unit should i put with these, and im also think of kicker component set up front, so im guessing i will have to run those components through the amp as well??? correct me if im wrong but the crossovers that come with the components are powered through the amp.... anyway i need ALOT of help.... Thnks in advance!