Wrote an article a few days back and posted it here: http://blogs.msdn.com/nickmalik/articles/243442.aspx

This article is directly aimed at folks who send software out to an outsource agency or overseas development shop, where the code is written and delivered back to you.  The article contains specific advice for how your RFP should read, or what your statement of work should say, to encourage the outsourcing vendor to use agile development methods instead of a waterfall software development lifecycle (SDLC), which nearly always fails.