Were you looking for a copy of Tierra (and, if so, did you find it)? I thought you (and perhaps others interested in artificial life), might be interested in a new phase of the Tierra project that I read about in a little freebie monthly magazine distributed around here. A new stand-alone version of the software was released Apr. 1st. A distributed version of the Tierra software will allow the connection of machines on the Internet. That enlarges the "Tierra universe" and provides more environments (niches) in which the a-life "organisms" can evolve. The software is available at
http://www.hip.atr.co.jp/~ray/tierra/ftp.html

and the article on metacomputing where I found this info. is (or soon should be) available at the Computer Bits web site,
http://www.computerbits.com/