A member over at HighRankings started a thread named How To Get Listed On Yahoo, Easily And Cheap, Proven method, no Yahoo-express, which provides just that. Here is how it works.
(1) Sign up for an expired domain name service that show sites listed in the Yahoo! Directory (2) Wait for the domain names to come into your inbox (3) Purchase the domain name for several dollars (4) Build up the site and content (5) Call Yahoo asking them to switch the site into the new appropriate category. He said, just tell them you changed businesses and tell them that you forgot the email address you signed up under. (6) Presto a free listing at least for the remainder of the service period, which could be for ever.
I am sure the Yahoo! Directory folks will patch this up shortly.