Here are a few sites I use to make banners. Feel free to check them out...you might even be able to make your own banners!
First, the program I use right now is paint.net. It's like MSPaint on steroids. You can get it for free here:
Some of the other useful sites I use:
Font Site #1
Font Site #2
Texture Site #1
Texture Site #2
UnFREEz - for making animated gif images
If you have any other sites you like, that are useful in making banners or other graphics, feel free to post them here!