I don't know if you can control them, but I've noticed we can't use the center tags, what's with that? Just thought I'd make you aware of it if you weren't already.
by the way, spudwick. you think you could show me the ropes on Photoshop? the program's so big i don't know where to start. or maybe make me a sig? then tell me how you did it?
Ahh ok guzman, I was just using the regular < center > tags, and they don't work.
It's pretty hard to explain without diagrams and stuff, you'll probably learn more from just trying stuff out yourself. However, I know of a site at netcorridor that can teach you a bit of stuff. There's probably better tutorials out there, but I pretty much taught myself.
If you are just wanting to do fancy headings like mine in my signature then all you really need to do is put some text on there. Then go to the blending options (Layer -> Layer Style -> Blending Options) and play about with those. Also play about with stuff on the "Filter" menu at the top. You'll be surprised how is easy it is to make a signature like mine or something equally fancy.