You will need to create a banner of 400x40 Pixels in "GIF" format and no more then 10k in size. After you Create you account you can up-load your banner to our sever from the Members page.

If you don't have a banner, there's no need to wait. You can start earning credits immediately, and design your banner ad later.

Here are some sites where you can create your banners online, for FREE!

• Instant Online Banner Creator
• BannerCreator.NU

Below are some good resources that can
help you create a banner if needed.
Advertising and Graphic Resources

http://www.raspberryhill.com/gifwizard.html use this when you're having problems getting your banner gif below 10k. GIF Wizard reduces image size up to 90% without sacrificing quality. 

http://www.bannertips.com/ this page has a bunch of useful information about banner creation, click thru rates, etc.  

http://www.killersites.com/1-design/ a downloadable color cube which has compatible colors for most browsers. Stay and browse this site--it's packed with tons of useful information for building websites.