Google Patent search lets you search by criteria - patent number, inventor, and filing date. It is similar to Google Book Search, which means that you can scroll through pages and zoom in on the text and images.
I've tried it out and got several server-not-responding errors, which were probably just coincidence. Other than that, it works fine, and will surely be an invaluable resource to all those folks who think that immeasurable wealth is just one patent away. I've immediately tried searching for a "Car seat with integrated side light", and - damn! - it already exists. So much for my dreams of wealth and glory.