My forearms suck as well- probably the weakest part of my body. In high school most of the lifting I did didn't involve heavy dumbells, which seem to help them over the long term- you might want to get off the machines?
Also, this site has tons of info on everything, and these workouts are some great ideas, I've included some in my workout already (kudos to who posted this):
http://www.bodybuilding.com/ , then go to exercises, then workouts, then just look under the tons of "Hardcore Training Programs"
Also- there was a thread not too long ago with some good info but I can't find it/it's gone.. Oh well. Hope I've helped.