Valve has announced an Early Access program that will allow PC and Mac gamers to purchase and start playing new titles while they are still in development. The company said a number of prominent titles have embraced this development model recently and found a ton of value in the process which is one reason they want to get in on the action.
The approach will vary by developer but interested parties are invited to check out the listing of Early Access titles on Steam and find something they like. Valve advises players to look at screenshots and videos of a game in its current state to gauge interest and check to see how often the developer updates the title.
Once you find something that interests you, simply buy the game or download it if it is free. Note that some developers will offer a discount for buying early while others may charge a premium for early access. This will all depend on their goals and the level of commitment and feedback they desire from Early Access customers.
As of writing, there are 12 games being offered in the Early Access program: Arma 3 Alpha, Kerbal Space Porgram, StarForge, Kenshi, Prison Architect, Kinetic Void, Gnomoria, Under the Ocean, Patterns, Gear Up: Premium, Drunken Robot Pornography, and 1...2...3... Kick It! Titles are in varying stages of production (some as early as Alpha) so take note of this before you place your order.