google offers a free translation api (known from google website translation).

just call via curl the floowing command:

curl -e http://marc.at6.net 'http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=merry+christmas&langpair=en%7Cit'

langpair describes the from and to language, google should use to translate your text.

more information can be found here: http://code.google.com/apis/ajaxlanguage/documentation/