Owners of Apple's iPhone and iPod Touch can now access more than 140,000 movies and TV shows after internet retailer Amazon launched its Instant Video app for the devices.

The free app lets Amazon Prime Instant Video members stream from Amazon's catalogue without incurring an additional charge, provided they have membership to Amazon Prime, which costs $79 a year.

Those without Prime membership can still download content through Amazon's video store for a fee.

"Our customers tell us they want the convenience of being able to watch all of their movies and TV episodes, wherever they are," said Anthony Bay, Amazon.com Vice President for Video. "Today we're excited to extend our 'buy once, enjoy everywhere' approach to iPhone and iPod touch users, giving customers the chance to enjoy more than 140,000 titles from Amazon Instant Video and more than 30,000 titles from Prime Instant Video anytime, anywhere."

Videos can be downloaded directly to your devices so you don't need an internet connection to view them. However, they can't be streamed via 3G or 4G, so you will need a WiFi connection to use the app.

The app doesn't support Apple's Airplay either, and you will need to access Amazon's Instant Video store using the Safari browser. But once a video is selected, it becomes available in the new app "in seconds" according to Amazon.

The app includes features such as "Your Watchlist," which lets customers make a list of all the movies and TV episodes they want to watch in the future, regardless of whether they own the video or not, making it easy to keep track of specific videos for later viewing. It also includes the "Your Video Library," feature that gives iPhone and iPod touch customers access to purchases and rentals from Amazon Instant Video on the web.

Meanwhile, Amazon has released its Cloud Player on 2012 Samsung Smart TVs and Roku streaming players, letting users access, browse, search, and play tracks from their music library through their home entertainment devices.

The Amazon Instant Video app can be downloaded from Apple's App Store. There is no word yet as to when the app will come to Android devices.