A new book, "Against Intellectual Monopoly" (on the economics of IP) by US economists Michael Boldrin and David Levine is available for a free download.

Here is the URL:
http://levine.sscnet.ucla.edu/general/intellectual/againstfinal.htm

The book is coming out in July 2008 from Cambridge University Press, but the authors have negotiated an arrangement with CUP to make it freely available online now....and keep it freely available.

Boldrin and Levine are trenchant critiques of the IP system and I think this book, focusing on both patents and copyright, will be worth a read.