Samsung has added Amazon Video On Demand and officially rolled out Blockbuster OnDemand to its LCD and Plasma HDTVs Series 650 and above and LED HDTVs Series 7000.

Owners of those select HDTVs can download the Amazon Video On Demand widget, which supports HD, for free from Samsung’s Internet@TV service. Amazon Video On Demand offers more than 50,000 movies and TV shows that are available for rent or for purchase.

There is no subscription for Amazon On Demand, users only pay for what they watch. Purchases are stored online in a user’s Amazon Video On Demand library so the movies can be accessed from PCs, Macs, and other devices.

Samsung’s Internet@TV service also offers widgets for Flickr, Yahoo! News, Yahoo! Weather, Yahoo! Finance, USA Today, YouTube, eBay, Showtime Networks and more.

The Blockbuster OnDemand service, first announced in July 2009, is available through a free firmware upgrade and is also available on Samsung:

• BD-P1600, BD-P3600 and BD-P4600 Blu-ray players
• HT-BD1250, HT-BD3252, HT-BD7200 and HT-BD8200 home theater systems

According to Samsung, Blockbuster OnDemand content can be streamed across multiple Blockbuster-enabled devices throughout a home. The video-on-demand movie rentals range from $2.99 to $3.99, while purchases typically range from $7.99 to $19.99. The deal also calls for Samsung Blu-ray players with the Blockbuster OnDemand service to be sold at Blockbuster stores nationwide.

Blockbuster OnDemand is also finally available on TiVo DVRs. The service will be included on TiVo Series2, Series3, TiVo HD, and TiVo HD XL DVRs. TiVo boxes will be sold at Blockbuster stores and online.