You'd be pretty hard pressed to find someone who would teach you about keyboards in person. You could try conventional music schools in your area, but you might have better luck online.
I can't remember from other posts what gear you have or how good you are, but I'd start with making sure you have good skills as a pianist first. If you don't, all you'll really be able to do in a band is pads. After that, I'd learn analog synthesis: there are good books that explain synthesis well (I have
http://www.amazon.com/Power-Tools-Synthesizer-Programming-Reference/dp/0879307730 and highly recommend it), or you could find online videos. Richard Lainhart has a series on synthesis that's available through the
http://www.jroc.us/ - Jordan Rudess Online Conservatory. Speaking of which, the conservatory is a great source for technical exercises. The other thing it has is clips from Jordan's Keyboard Madness video (which you could get separately as well), which give you a lot of good ideas for keyboard layers and splits as well as lead playing, using the pitch bend wheel, and so on. Basically, you're going to have trouble finding someone to teach you how to use your specific keyboard (although there are instructional DVDs for some keyboards; Yamaha's Motif series has that kind of thing); what you probably need more is ideas on what you can do, and then spend some time with the manuals or asking around here or manufacturer-specific forums on how to do what you've thought of.
I suggest spending some time learning analog synthesis first because many modern keyboards either use analog synthesis directly or use techniques based on analog synthesis. If all you want to do is use preset sounds from your keyboard, this isn't that necessary, but if you want to really dig into your keyboard, having some idea about the building blocks it uses will help a lot.
