Garmin Voice Studio
Can you do a killer impersonation? Have kids? Want your GPS to curse like a sailor? Well hang on, because the boys in Olathe have released Garmin Voice Studio, a free Windows application that will let you add your own voice prompts to most nuvis and a few other products.
Basically, you record a few dozen phrases and use Voice Studio to edit and load them to your device. The entire process is supposed to take less than 30 minutes for most folks. Sorry, no text-to-speech though, so you’ll have to give up on hearing street names, at least until the novelty of having your six-year old call out directions wears off.