TheServerSide website have two very good whitepapers on outsourcing , still working my way through them so will update this post later.
http://library.theserverside.com/detail/RES/1128700921_997.html?src=sponsor_res
http://library.theserverside.com/detail/RES/1128700921_599.html?src=sponsor_res
Paul Browne 