I'm booked in on a beginners course with Lisa Munroe at the end of January. www.airbrushes.com
My airbrush has been lurking unused in a cupboard since Cake International 2 yrs ago so I decided this was the only way top overcome my fear of it. Lisa was very helpful when I spoke to her.
I think the airbrush I bought came with Kroma colours but I since found some Americolor at the Cake Decorating Company in Nottingham.