Using Google's Custom Search Engine, with Javascript: http://mdlwas.clst.org/search.html
Using the Google Mini search appliance, plain vanilla: http://search.minitex.umn.edu/search?site=mdl&client=plain&output=xml_no_dtd&proxystylesheet=plain&proxycustom=%3CHOME/%3E
Using the Google Mini search appliance with significant XSLT and Javascript massaging: http://search.minitex.umn.edu