The channel will spend an eight-figure sum on the productions, all adaptations of books, during 2008/9. Additionally, it is setting up a £1m development fund for various other HD projects.
The first of the trio is a novel by former SAS man Chris Ryan, Strike Back, about a British military hero and a fallen war veteran now living rough in London. The pair used to know each other and are reunited by a Middle East hostage crisis. Indie Left Bank Pictures is making six hour-long episodes.
Children's book Skellig, by David Almond, is also on Sky One's list. It tells the story of a young boy called Michael, whose sister is seriously ill, and a magical creature called Skellig living in his garage. A two-hour television version is being made by Feel Films.
The third production will be previously-announced Terry Pratchett adaptation Going Postal.
Mob Films is making two two-hour specials following its version of Hogfather last year and The Colour Of Magic, which will air this weekend.
Sophie Turner Laing, Sky's managing director of entertainment, said she was opting for adaptations because of the channel's lack of UK drama experience.
She wants to venture into original commissions in coming years and said drama was "very much a long-term plan".
"We want to walk before we can run," said Laing. "Sky One has a history of importing quality dramas and, apart from the long-running Dream Team, British drama was the one bit of our DNA that was missing.
"As we are not renowned for drama, it made sense to go for stories that already have a knowledge base."