Currently Being ModeratedDec 24, 2011 11:52 PM (in response to Sweejak)
The upgrade from Aperture 2 to Aperture 3 is not free, so you will have to buy an upgrade licence. AP 2.1.4 was the last free upgrade.
I'd recommend to buy the current version AP 3 version from the App Store http://itunes.apple.com/de/app/aperture/id408981426?mt=12, and not the boxed upgrade from AP 2 to AP 3. The AppStore version is much cheaper, and the licence is valid on all machines you own.