Rocker Panel Question?????

I just got a 91 Explorer XL and I would like to fit it up a bit. It has some rust on what I think are called the rocker panels. The rust is right in front of the rear wheels on the bottom panel. I would like to know where I can get some replacement panels. Also are the any tricks to replacing them??
Thanks for any and all info.... Larry

 

[MONMIX]

Just remember to cut out ALL the rust. Go about one inch beyond the infected area.