There's a new kid on the search engine block called Acronyma . It's a database of over 450,000 acronyms in seven languages that allows you to search by word(s) or acronym. You can submit new acronyms (I did after searching for Interpol and coming up empty) and also look up statistics on how many acroyms have been added in each language. Nifty!
A tip o' the Mickey Mouse ears to Research Buzz  for the link.