This is the only decent website on the net that shows you tiered affiliate programs and only that.  All programs listed on this site have at least 2 tiers.  I'm positive that there are other affiliate program directories out there that are more extensive than this one, but I have yet to find one that is only tiered programs.

I've researched every affiliate program on our site and I have used most of them.  I wouldn't have listed them here if I hadn't done well with them or thought that they would do well.

If your looking for a resource to start building your sub-affiliate base, you've come to the right place.  The ability to make money from others' work can be a very wonderful thing.

I also have a section with tips and advice for affiliates.  I'll constantly be adding more information from choosing an affiliate program, to basic design, to SEO, to help you earn more with your merchants.

There is also a section containing many recommended tools for webmasters.