There are two things you want to click on the spell trainer. There's a link for all the spell skills, and a link for specialization which is listed by the skill name itself.
One thing I've noticed on two toons I have in the cg, the skill trainer only trains to 300 when the cap for both my toons is 310, so I actually lost a little skill by training. Not a huge deal though, since getting 10 points back in a heavily used skill beats trying to train divination up from scratch.
