Also available on Ebay, which is where I got mine.
http://cgi.ebay.com/REMINGTON-7600-7...item335a3594bb

It's very simple, all you need is a mallet, punch and needle nose pliers. Tap out the pins for the trigger group, remove the spring, install new one and reinstall trigger group. It comes with directions. Start to finish less than 10 minutes.