http://www.cs.uu.nl/people/franka/ref

A link collection of programming language theory texts and resources, all of which are freely available over the Internet.

BrokenLink

[All I can find is in the web archive 11-09-2009.] http://web.archive.org/web/20070407180509rn_2/homepages.cwi.nl/~atanasso/

http://www.cs.uu.nl/wiki/Techno/ProgrammingLanguageTheoryTextsOnline