Walmart announced Wednesday support for the iPad with its VUDU streaming movie service. What’s intriguing is that it’s doing this through a Web app rather than a native app that runs on iOS.

[ad#Google Adsense 300×250 in story]That enables Walmart to skirt around in-app purchase fees imposed by Apple – a similar move to Amazon.com, which has introduced Kindle Cloud Reader for Mac, PC and iPad.

VUDU’s library includes “more than 20,000 blockbusters, Hollywood classics, independent films and TV episodes,” according to the company.

VUDU differentiates itself from Netflix and other on-demand movie streaming services by offering what it bills as “the world’s largest online selection of HD movies,” encoded with Dolby 5.1 surround sound, offered on the service the same day they come to DVD and Blu-ray.

Movies purchased or rented using the VUDU app can also be viewed on the Web site, as well as other devices that support VUDU. Walmart counts more than 300 such products, including some TVs, Blu-ray Disc players and the Sony PlayStation 3.