As of August 14, 2009, TILT has been removed.  The Open Public License version will be available until May 2010 in case anyone wants to download it and host it locally, and then it will be taken down as well. 
More information about the decision.

The following documentation was written by the TILT developers to assist individuals and institutions interested in downloading yourTILT. The files are currently available in HTML as follows. Although we cannot provide technical support, people subscribed to the TILTTALK listserv may be able to share their expertise.