If you're looking for good upgrade and replacement hardware, Stewart-MacDonald is the place to go. http://www.stewmac.com. They're a luthier's supplier and carry all the wiring, pickups, potentiometers, switches, et al, that you could ever need. All of my guitars have been rebuilt with their products. For about $50, you can make a $100 guitar sound like a thousand dollar guitar.

Also, if you check out Seymour Duncan's website, they have tons of very decent wiring diagrams, which can be a help when wiring everything together.

BigO, your epiphone, if it has the stock hardware, has about the cheapest components known to man. When I bought my epiphone les paul custom, the first thing I did was rip out all the hardware and replace it with SwitchCraft hardware. Its not hard, and your guitar will sound tons better.