I don't know if you're aware of O'Reilly Safari which is an online bookself. It's a great resource - especially if you are a travelling consultant or simply need/wants online access to your books. I have been a subscriber for a while and can recommend the service. Now, in corporation with Sun Microsystems O'Reilly is offering a 30 day access, free of charge, to the system (normal trial period is 14 days). Apart from the book titles you'll also be entitled to access to a couple of free web courses incl. "Introduction of Java Programming Language" which might be of interest to some.
"Sun now has a partnership with Safari Books Online and you can get free 30 day access to over 1700 IT online books, which includes the great Sun Press books as well as four Sun web courses."