Kits are (mostly) generic based on woofer size. One of my favorite sites, Parts Express (why is the URL replaced with asterisks?!), sells speaker refoam kits. Determine the size of your woofer, order the kits, and refoam away. Be very careful when refoaming - if the surround isn't well centered, the voice coil will scrape the edges of the magnetic gap, which is considered bad.
I have yet to undertake my first refoaming experience on a the woofers from a pair of Criterion 4120's. I paid $10 for them, which included a Hitachi receiver and a JVC CD player from 400 years ago that still works great - so I'm not too worried if I screw up.
