Odds Ratio MDR
A version of our Multifactor Dimesnionality Reduction (MDR) method that uses odds ratios to determine high-risk and low-risk genotype combinations prior to constructuve induction is available as a package for R called ORMDR. I haven't had time to try it. Let me know if you like it or find it useful.
Here is the paper that describes this approach:
Chung Y, Lee SY, Elston RC, Park T. Odds ratio based multifactor-dimensionality reduction method for detecting gene-gene interactions. Bioinformatics. 2007 Jan 1;23(1):71-6. [PubMed]