Check out these sites. www.thelearningpit.com www.plcs.net
I work for a plc company ( www.automationdirect.com
) where I do tech support for VFD's and starters.
Understanding PLC's and how they interface with drives and motor control systems is the majority of my call load.
When someone is learning plc's, I always recommend getting one and either a handheld or the software to try them out. It's the best way to learn.
I have seen quite a few in-expensive plc's on ebay, including some cool training courses.
Don't worry guys....I'm not in sales. I just answer the phone:) It sure beats the steel mills. And Georgia is a lot warmer than Chicago...