Ah okay, I use PhotoshopCS3 and it's probably pretty similar. Have you read through many tutorials for sigs? I could probably whip up a tutorial for you too, or find a couple for you to start with so you can practice a bit more. The banners are pretty good though =]
Here's a theme design I just made for a contest, Halloween themed:
http://z3.ifrm.com/209/108/0/p456587...ntree_copy.png