Valve Software’s Source Filmmaker is available now as a semi-closed beta for Windows 7. It’s the real-time tool used to create Valve’s own promotional animations for games such as Team Fortress 2.
It’s licenced for commercial work, provided you don’t pinch any of Valve’s in-game assets. To snag a beta licence key now, contribute a shiny 3D item to the Team Fortress Workshop, TF2′s internal marketplace for fan-made items. Doing this gives you a better chance of getting a licence key.
For a complete set of tutorial videos, take a look at the YouTube channel.