Mio Tech has just announced a special one-time offer for one Free Map Update for Mio Moov and Knight Rider GPS customers, who purchased a unit between 4/1/2008 and 1/20/2009.
You must register first, otherwise you have to purchase it later on. Please see this page for details. They have a new web site up for registration.
There is no mention about updates for older GPS, maybe we should complain to Mio Tech.