Yes, tihs is a calssic. And I wnoedr if tehre eevr was any reserach bhenid it at all.
I was ocne broed at wrok and worte a porrgam taht tkaes a peice of txet and randmoly mxies up the lteetrs isndie ecah wrod taht has mroe tahn trhee lteetrs in it, laeivng the frist and the lsat lteetr unchagned. Not too oriignal, but hree it is:
http://mbm.dotnet11.hostbasket.com/obfuscator/ (Aapprnetly the pgae olny wroks in Intenret Explroer. I hvaen't had a cahcne to fix taht yet. Hvaen't been mcuh broed at wrok ltaley!)