Ok so Yahoo has quite a nice Aff offer at the moment :

Start with £50 credit in your new Yahoo! Search Marketing account for a limited period only.

and the kick back is Very Good too !

Yahoo! Search Marketing UK Terms and Conditions July 2007

Yahoo! Search Marketing’s policy on PPC (Pay-per-Click) search engines including Miva, Yahoo! Search Marketing, Google and any other search engine that offers full or partial Pay-per-Click advertising

Yahoo! Search Marketing’s policy regarding the protection of our brand name in association with PPC is as follows. Affiliates who are part of the Yahoo! Search Marketing affiliate programme with Commission Junction will be prohibited from the following:

1. Using Yahoo! Search Marketing’s brand name, brand name misspellings or similar variations in the written copy of adverts on PPC search engines.

2. Using Yahoo! Search Marketing’s brand names, brand name misspellings or similar variations as keywords or key phrases for the purposes of targeting adverts on PPC search engines.

3. Using Overture’s brand name, brand name misspellings or similar variations in the written copy of adverts on PPC search engines.

4. Using Overture’s brand names, brand name misspellings or similar variations as keywords or key phrases for the purposes of targeting adverts on PPC search engines.

Any affiliates found to be in breach of any of the above will be put on notice and if this process continues this may result in their account being permanently excluded from the program.