The Steam trading beta we mentioned a month ago has stumbled out of the beta wilderness into the bright sunshine of a full release. Valve's own Portal 2 and free to play MMO Spiral Knights are the first games outside of TF2 to join the trading program, which means you'll be able to swap Team Fortress 2 and unredeemed Steam games for Spiral Knights loot and gear from the Portal 2 item store .
Valve announced the launch of the Steam trading beta on the Team Fortress 2 blog , where they also mention that more than a million items have been traded in the beta period. "To celebrate, items are on sale in the Team Fortress 2, Portal 2, and Spiral Knights in-game stores," the blog post says. To invite someone to trade, open up a Steam chat window, open up the drop down menu next to their name and select "invite to trade." For a full run down of how trading works, check out Valve's Steam Trading FAQ .