Recommended reading for Recommender Systems?

I'm looking at working on a project that will involve a recommender system and was wondering if there was any reading that people here would recommend. I've done a little poking around and found quite a few papers and the equivalent of text books. Knowing that these things can vary greatly in quality and practical application I was hoping there might be a few people here that could recommend a book/paper/website or two.

Thanks

Mike