The Online Psychology Lab, linked to the net in May 1997 by Donatella Pagani and Luigi Lombardi, University of Padua
An exciting lab with web experiments (they call them tele-experiments) on human perception, cognition and behavior, located at the Max-Planck Institute for Biological Kybernetics. Marvellous realization, check it out!
Cool design: A large collection of classic experiments and background information was put up in February 1998 in the Internet Psychology Lab at the University of Illinois at Urbana-Champaign.
Since september 1998 psycholinguist web experiments (web experiments on language and language processing) can be found at the Scottish laboratory by Christoph Scheepers (Glasgow University) and Martin Corley (University of Edinburgh).
High quality online surveys and a number of web experiments can be found in the ZUMA Online Lab. Currently, the studies are in German language only, sorry. Wolfgang Bandilla and Michael Bosnjak make up the local OnlineResearch team. The WebLab has been cooperating with them since the ZUMA team was first established in Mai 1998 (and even before ;-).