Jim Beaver (Bobby Singer) posted a new entry on his MySpace, confirming the Harper's Island rumors. Beaver will have a regular starring role on the CBS new series, which also stars Katie Cassidy (Supernatural's 'Ruby') and Christopher Gorham (Ugly Betty's 'Henry Grubstick').
"Harper's Island is a murder mystery that unfolds as friends and family attend week-long festivities at a destination wedding on a secluded and picturesque island off the coast of Seattle, infamous for a homicidal maniac's rampage seven years ago." Source.