Check this out.
The guys form PACKT Publishing: http://www.packtpub.com/ have a celebration these days. They've published their 1000th title in the area of IT literature. So for the next three days (28th to 30th of September) they're giving some eBooks as gifts to their registered users. The nice part is (if you're such one) that you may search for any one of those 1000 books to pick up. Any book! Maybe that's why their site is currently so overloaded ;) I guess I'll have to wait a while to browse the store.
One thing is for sure - it will be hard to choose with so many interesting titles.