You could also get a copy at Barabási's homepage.

http://barabasi.com/publications/24/network-science

PSA/headsup - this is the best copy, it contains the diagrams and figures.

Direct link: http://barabasi.com/f/95.pdf

(Unfortunately the <a> link on the site has `download="Paper.pdf"` inserted unhelpfully. This direct link won't suffer from that problem.)

This is formatted more neatly than the copy I found, but it's missing the diagrams and figures.

This link may or may not work: http://dacemirror.sci-hub.la/journal-article/8a98ee98ed5bf80...

After a little digging, I was able to find http://sci-hub.la. Really sad they're having domain issues :( (direct IP access seems to be a little broken at the moment)