Came with a mini CD driver disc, I installed the Windows driver (you have the option to install a utility or driver but I did driver only and used windows wireless config instead) onto a vista PC. Reasonably quick installation and then plugged in the WiFi dongle, immediately it found the wireless network, connected no problems and surfing the net in just a few minutes. At this price it's a great product...so far!
For the price of this device I got a fantastic deal! The signal quality is much improved than my Laptop's internal wireless adapter. I usually carry my laptop around in the house, before buying this I used to get so annoyed when the signal kept breaking but now I'm always on full bars.
Brilliant product, great affordable price. Would definitely recommend!