I just found some good websites:
LookyBook, a site that lets you read picture books online in full. Here's one by Istvan Banyai and here's what I've assembled on my bookshelf so far.
Thumbtack Press, a site for buying and selling prints,
and The Sartorialist; I read an interesting article in Saturday's Guardian magazine, about this guy named Scott Schuman who goes around taking photos of well dressed people on the street for his blog. Even though he's just walking up to people and taking their photos, he still manages to get brilliant compositions and backgrounds.