While much of my advice is for organizations dealing with outside contractors or web development agencies, many organizations choose to actually hire web developers. If you go that route, I suggest reading this excellent post by Laura Thomson on managing engineers. Engineers are like other skilled white collar professionals, but more so in many of the ways that reward manager-as-servant mentalities.
You’ll also need to hire them, and this post at Autodidacticism, while aimed at developers, covers the non-techical things you’ll want to look for in an engineering recruit. Much of the theme of this blog is that both developers and those working with them forget that success depends a lot on non-technical factors that the myth of technology as magic and engineers as robotic, mysterious, yet interchangeable resources obscures.