I just came across this magazine site:

http://issuu.com/home

Go there and type Amiga, or anything else you like, such as Gaming, Retro, Photography. They have thousands of magazines and books in PDF format to look through online, via a mobile app, or to download as PDFs.

This is all community driven with people able to register then publish their own scanned books and magazines to the site to expand its database. Very cool.

Might not be 100% legal, but for a retro book and magazine resource it is pretty cool.

Plus for other more up to date stuff it looks like a great resource too.