Fiberglass repair?

Could someone post a good link for fiberglass repair instructions? I haven't been able to find what I am looking for with a search.

I have a large crack in a fender that I am going to try and fix. I have worked with fiberglass before...but that was building custom speaker boxes. I haven't tried to repair a body panel. And I don't want to remove it from the car if it is at all possible.

Thanks!