One of the options on the Official Harry Potter website is to download ringtones - one of which is of Lord Voldemort talking. That audio can now be downloaded online. Ralph Fiennes, as the Dark Lord, says, "Step aside Wormtail so I can give our guest a proper greeting." It can be downloaded from this page. Needless to say this will be a 'Goblet of Fire' film SPOILER.

Source: The Leaky Cauldron