If you are willing to give Google Chrome 11 beta release or the current version of Google Chrome Canary build a try you'll find an interesting little piece of functionality supported. Using either of these browsers, a microphone, and some html 5 code embedded in Google's translations page you can dictate the word(s) or phrase that you wish to be translated. No joke... it works well too!
Simply look for the microphone icon in the lower right side of the input text box and click on it, you must have your mic on of course and you are only afforded a few seconds to input your command. If you want to play around a bit you can also go to the sandbox app created by Google. A headset mic might work best but my testing with a desktop mic has produced good results.