It turns out that the most promoted Machine Translation Systems on the web are currently Google Translate and Systran (used to be and most probably is a benchmark for machine translators for European languages). It was curiously to find more and after diving with Google I managed to find a nice page with more than 100 machine translation systems, some of which are available as demos online.
Only an excerpt:
http://www.sunda.fi/eng/online_demo.html (Finnish Company)
http://www.systran.co.uk/ (originally established as U.S. company and further moved to Paris)
http://www-01.ibm.com/software/pervasive/tech/demos/translation.shtml (IBM used to be a pioneer in Machine Translation)
http://babelfish.yahoo.com/ (translation technology is provided by Systran)
http://www.promt.ru/ (Russian monopolist emerged from Herzen University, Saint-Petersburg).
Try out more!