Don't know someone posted it or not, but it is worth to post again.
Check this out

fxp://scientific-library.net/pub/data/unsorted/2004.06.22

- Lot of cisco, programming, and other good books.
- Most of them is on djvu format, download djvu plugin from here

hxxp://www.lizardtech.com/download/dl_download.php?detail=doc_djvu_plugin&platform=win

Enjoy!