http://it-ebooks.info/
You can search a vast majority of many (full) IT (Information Technology) books in PDF format. There's even a QR code so you can download it to your phone.
These are the main features of the site:
Book details.
Book description.
QR codes.
Link to buy the book.
Sharing via social media.
Subscribe to get updates of new books via email.
Direct downloads.
No signup or captchas.
I already downloaded over 3 GB of books from this site and I'm still continuing to do so. I even have my own library on my hard drive. xD Enjoy!