And don't forget the H.P. Lovecraft Historical Society's lovely CDs.
They are not free, but well worth buying for Lovecraft fans. They're very true to the original works, and come with all sort of great inserts, like maps and stuff (to make the physical disks definitely worth getting)
Oh, and a note - I didn't actually add any characters to Dunwich (except a librarian) who weren't at least mentioned in the original story. Even Armitage's wife and doctor are noted in passing. The biggest change was making Zebulon Whateley female ("old Widow Zebulon), since Rhys had a better grasp of the accent than any of the guys in my cast.