In a long-expected move, web-based TV provider Hulu announced that it will soon begin offering a premium subscription service called Hulu Plus. The service will cost $10 per month and provide unlimited (but ad-supported) access to full seasons of new and old TV shows. Best of all, it will eventually be offered via iPhone, iPad, select Blu-ray players and HDTVs, PlayStation 3, and Xbox 360, in addition to today's web-based services.

"Hulu Plus is a new, revolutionary ad-supported subscription product that is incremental and complementary to the existing Hulu service," Hulu CEO Jason Kilar wrote in a blog post. "For almost all of the current broadcast shows on our service, Hulu Plus offers the full season. Every single episode of the current season will be available, not just a handful of trailing episodes ... you'll also have access to back seasons or full runs of some of TV's greatest shows."

Hulu already offers a decent collection of TV shows from most of the major US broadcast networks, including ABC, NBC, Fox, and others. But the free version of the service typically offers just the five most recent episodes of new shows and a selection of older content. The Plus service will provide much more content, including entire TV show seasons and more older shows. It doesn't include cable networks such as HBO, however.

For now, the networks are hoping that Hulu Plus will be additive and not replace the far more expensive cable TV plans that are currently common in the United States. It may take a while to find out: Hulu Plus is currently available only as part of a limited, invitation-only beta. Hulu hasn't said when it will be rolled out more broadly.

Hulu is currently the second most popular video service online, behind YouTube. But Hulu watchers spend a lot more time on that site than do YouTube viewers, and they watch an average of 2.7 hours of video per month.

If you're interested in the Hulu Plus beta, you can request an invite on the Hulu website.