During the last decade, the cost of recording and producing music and video has plummeted, giving amateur auteurs a chance at stardom. But at the same time, the expense involved in making video games has gone up: the development kits needed to create games for the consoles made by Microsoft, Sony and Nintendo cost thousands of dollars, and those companies usually send the kits only to established producers.

Microsoft is trying to change that. Today the company is expected to announce the fall release of a product called XNA Game Studio Express, a basic version of the company’s game authoring tools that will let aspiring designers write games on a PC and test them on an ordinary Xbox 360. (To test games, the designer pays $99 a year to translate the game from the PC into the Xbox format.)

For Microsoft, the goal is to inspire amateurs to share or sell relatively simple games on the company’s Xbox Live network. (Microsoft will not own any rights to products created with these tools.) Programs created with XNA Game Studio Express will not look as good as most packaged titles. But at a time when gamers seem tired of sequels and genre standards, the company says it believes that some kind of independent games business could provide a breath of fresh air. “We thought a lot about ‘The Blair Witch Project,’ ” said Scott Henson, a director for Microsoft’s game developer group, referring to the low-budget horror film that became a surprise hit in 1999.

And, of course, the company hopes the process of making games proves as addictive as playing them. “On the Internet, we’re going from a monologue world to a dialogue world,” Mr. Henson said, referring to sites with user-created content like MySpace and YouTube. “It’s amazing how much participation there is.”