Starting in 1999, Acorn Media has released all of the first series of Wimsey film adaptations on both VHS and DVD. Acorn Media has a wonderful interview with Ian Carmichael on their site which provides a good history of his struggle to get the films made. You can find it here.
Film Adaptation Availability
Series 1 (Ian Carmichael)
Series 2 (Edward Petherbridge/Harriet Walter)
As the bulk of the membership of LordPeter is American, I have chosen to link to editions which will be readily available and playable in the U.S.