The video site best known for its library of TV shows launched on Tuesday a paid subscription service that will also be supporting by advertising. Hulu Plus, which is available initially only by invitation, will make it possible for users to access their favorite sitcoms, dramas and more over many devices beyond a Mac and Windows PC.

Subscribers to Hulu Plus will gain access to the full season of all the current shows offered by Hulu, not just a handful of episodes that's available for free. In addition, users can access the shows through a Hulu-provided app for the Apple iPad, iPhone 3GS, iPhone 4 or third-generation iPod Touch.

Hulu Plus apps will also be available for select Internet-connected TVs and Blu-ray players from Samsung Electronics. Hulu plans to support other devices in the future, but did not offer a timetable or list. However, the site said an app for Sony's PlayStation 3 video-game console is "coming soon."

Hulu, which is co-owned by News Corp., NBC Universal, The Walt Disney Co., and others, offers TV shows from 100 providers. While the offering has been free, industry watchers have speculated for quite awhile that a paid service was likely.

However, charging for TV can only be successful if the content isn't readily available on paid TV, video on demand or regular programming, analysts say.

Nevertheless, studios are likely to continue pushing to find ways to make money off of their shows on the Web, given the appetite for online video. A total of 183 million U.S. Internet users watched 34 billion videos online in May, according to ComScore.

Hulu is charging $9.99 a month for the Plus service. People can request an invitation for access to a preview of the service. Hulu plans to increase the number of subscribers gradually, and did not say when Plus will be generally available.