I bought this:
http://www.hellolights.com/index.asp...ROD&ProdID=166
and this:
http://www.hellolights.com/index.asp...rodID=462&HS=1
The rest is piece of cake.
The hardest part is deciding whether to cut up the MH plugs between ballast and fixture. The ballast doesn't fit inside the ballast box so I used another ballast box. But I removed that nifty three prong plug from the original ballast box and installed it into the new ballast box so I didn't have to cut any MH wires coming from the fixture.
My best advice is to open up your fixture, look at how the lights are wired to the ignitor, and how the same wires are connected to the fans. Then read the above thread and it will all make sense (assuming you know the difference between neutral, hot, and ground)