There are a few videos on the "BBC Comedy" website.The first one doesn't contain spoilers in my opinion, but the others do.

WARNING: SPOILER ALERT!!!!

Deeply Dippy (Song from David and Maureen's 'Cheering-Up tape'):

__a href="http://www.bbc.co.uk/comedy/clips/p00ghx6y/psychoville_deeply_dippy/" __http://www.bbc.co.uk/comedy/clips/p00ghx6y/psychoville_deeply_dippy/

WARNING: SPOILERS!!!

David Performs Les Miserables (scene from Episode 1):

__a href="http://www.bbc.co.uk/comedy/clips/p00gmwsp/psychoville_david_performs_les_miserables/" __http://www.bbc.co.uk/comedy/clips/p00gmwsp/psychoville_david_performs_les_miserables/

Overdue Books (scene with Jeremy from Episode 1):

__a href="http://www.bbc.co.uk/comedy/clips/p00gmwtt/psychoville_overdue_books/" __http://www.bbc.co.uk/comedy/clips/p00gmwtt/psychoville_overdue_books/