[karolisd]

The book Programming Collective Intelligence has a step-by-step example of how to build a recommendation system. Highly recommended.

[jfaucett]

I can second this. It gives plenty of working examples and lays enough groundwork so you can dig deeper where you need to.

[tmaly]

I have the book sitting on my desk, but I have not read it yet. Thanks for pointing this out, I have been wanting to do something with recommendations.

Cheers