Where to Get the Games

The entire X-COM series is now owned by Take Two's 2K Games division and is no longer abandonware. Here's a list of retailers where you can buy the original Microprose games legally, either in a bundle or individually:

Digital Versions

Activated on Steam

• Steam Store
• Amazon
• GamersGate
• Green Man Gaming
• Humble Store

For more info, see Steam Versions.

Standalone from GOG.com:

• UFO Enemy Unknown is called "X-COM: UFO Defense" there.
• X-COM: Terror From The Deep
• X-COM: Apocalypse

Physical Versions

If you don't mind paying more for something more old-fashioned, there's always eBay and Amazon.