@ ve1n: Thanks man!

It's so smooth
@ breaker: Ah, thanks..Well technically there are no size constraints. The banner will not stretch the page since it's a background image, however... we try to keep the banner size under 980px width so it fits in all browser resolutions. You will notice with this new skin, the background image is 990px, but there is a solid color behind the banner and it fades in - this way if someone is using a large resolution the banner wont just get cut off, but rather it will blend into the solid color that is filling up the container...
Here is an example. In the following image, I changed the background color behind the banner so you can see that it does get cut off....

however in the skin I use a solid color that matches the banner....

To answer your question....
If you want to make a fixed width banner that is similar to the ones on other other skins that doesn't stretch 100% like this skin does then keep it around 920px, if you plan to make a banner that can stretch just make sure one of the sides can fade into a solid color so it won't just get cut off or looks strange.
As far as height, it never matters the height for a banner, but use your imagination. What I mentioned above is very technical....If you just want to keep it simple, make a banner however you want, and we will make it work!
