The Internet Archive working with some Canadian Libraries are building a new
collection (but still in beta).
If features color scans, djvu including OCR for searching, and some include pdf (done by HP-labs)
This collection will be adding books each day since they are using a cool new page turning robot. The next step will be to ramp up this project by adding scanning stations and more libraries.
Enjoy and please provide feedback in the forums in that collection.