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The Google Directory also has numerous links to information about plagiarism detection devices at http://directory.google.com/Top/Reference/Education/Educators/Plagiarism/Detection/.
Joint Information Systems Committee (JISC): Electronic Plagiarism Detection
http://www.jiscpas.ac.uk/apppage.cgi?USERPAGE=6588
JISC completed a plagiarism project in 2001, and they are establishing a plagiarism advisory service as a result of this experience. There were 4 parts to their plagiarism project, and they include:
1. Technical review of free-text plagiarism detection software 
2. Technical review of source code plagiarism detection software 
3. A pilot of free-text detection software in 5 UK institutions 
4. A good practice guide to plagiarism detection
A listserv has also been to continue discussions dealing with academic dishonest and plagiarism issues.
A copy of JISC's Technical Review of Plagiarism Detection Software Report can be accessed at http://www.turnitin.com/static/pdf/luton.pdf.
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JISC Plagiarism Advisory Service
http://www.jiscpas.ac.uk/
JISC Plagiarism Advisory Service is a new offering that began in September 2002. It is based in the Information Management Research Institute at Northumbria University (UK). New materials are constantly being added to this plagiarism portal, but it currently offers advice & guidance, educational materials for students and other online resources. A plagiarism detection service, supported by the Joint Information Systems Committee (JISC) until August 2004, is based on the turnitin.com platform and allows instructors to conduct electronic comparisons of work complete by students.
JPlag
https://www.ipd.uni-karlsruhe.de/jplag/
Guido Malpohl initially developed this software which is designed to detect academic dishonesty. The software does more than merely compare the text of documents. JPlag also looks at program language syntax and program structure so it can also be used to detect stolen software parts. Instructors may use JPlag for free, but they must first set up an account in order to prevent unauthorized use by students.
Library Electronic Databases
http://www.library.uiuc.edu/orr/
The Library at the University of Illinois at Urbana-Champaign provides access to numerous electronic resources for students and faculty. Instructors may want to consult these resources when checking for plagiarism. Full text databases like EBSCO and Expanded Academic ASAP (InfoTrac) are two obvious starting points when checking undergraduate assignments. One thing to keep in mind is that some resources that are not full text but provide abstract information are often used by students.
Moss
http://www.cs.berkeley.edu/~aiken/moss.html
Moss or Measure of Software Similarity is a tool that has been used primarily to detect plagiarism. The way it works is that it detects similarities of C, C++, Java, Pascal, Ada, ML, Lisp or Scheme programs. Moss is free to use for instructors and staff of programming language courses only.
Plagiarism.org
http://www.plagiarism.org 
University of California Berkeley students and alumni created plagiarism.org to be used to detect plagiarism. One thing to watch out for is that the software doesn't differentiate between quoted materials and original writing. 
The Plagiarism Resource Site
http://www.plagiarism.phys.virginia.edu/
Lou Bloomfield, Professor of Physics at the University of Virginia, is the sole author of The Plagiarism Resource Site. The goal of this site is to ""help reduce the impact of plagiarism on education and educational institutions"". Numerous links are provided to sources on how to deal with plagiarism.
Turnitin
http://www.turnitin.com/
Turnitin, a plagiarism.org partner, considers themselves to be ""the world's most widely recognized and trusted resource for helping prevent Internet plagiarism"". Free trials are also available, and subscription costs vary depending on the type of plan chosen.
Turnitin is currently the subject of a copyright controversy. For more information, check out the following article, ""A Plagiarism Detection Tool Creates Legal Quandary"" at http://chronicle.com/free/v48/i36/36a03701.htm.
WordCHECK
http://www.wordchecksystems.com/
WordCHECK is used by a diverse group including information researchers, copyright attorneys and classroom teachers. This plagiarism detection device was developed by Information Analytics, a Lincoln, NE company owned by Kenneth Livingston and Mark Dahmke. WordCHECK may be purchased for a fee.
Comparison of Plagiarism Detection Tools
 Comparison of Plagiarism Detection Services
http://www.wou.edu/provost/library/about/staff/kincanon/plagiarism/chart.htm
Theresa Gillis, Eastern Oregon University and Janeanne Rockwell-Kincanon, Western Oregon University, comp