The VOD service, known as MSN Video Player, has been in beta phase since last summer, with a select group of users watching content on the site from deals with BBC Worldwide and All3Media.
Microsoft has now agreed additional programming deals with independent product firms Shed Media, RDF Media and the Digital Rights Group, which handles many primetime ITV1 shows.
The company further holds a separate agreement with Pact - the UK trade association for independent TV and film producers - which stipulates full licensing terms for on-demand content, including availability periods and potential exclusives.
Users on MSN Video Player will also be able to access the MSN Video service, featuring short-form clips such as film trailers and news items.
All content on the service will be available free-to-view and Microsoft intends to offer high definition programming and films later in the year using its Silverlight technology.
During the opening 11 days of the beta last August, MSN Video Player pulled in a total of 167,487 video views by 154,841 users, with That Mitchell And Webb Look, How to Look Good Naked and Peep Show among the most popular shows.
Microsoft UK managing director of consumer and online Ashley Highfield declined to reveal the exact number of users now signed up to the service, but did say that they are watching an average of 25 minutes of material a month.
"Not all video players are equal. Our average viewer watches for 25 minutes, significantly higher than other online services," he said.
"It shows we're doing more than slapping on any programme for people to watch."
However, MSN Video Player will face stiff competition in the market from Arqiva's SeeSaw VOD service, which launched out of its own beta last month.
SeeSaw currently offers around 3,000 of on-demand programming but will launch a paid-for service with around 2,000 hours of premium content by the end of June.