Just noticed BioProcess International's latest (January) issue with a supplement devoted to process control in biopharma, written by
Christian Julien and William Whitford. It provides an excellent and thorough review of the subject.
I know from personal experience that many of you hate to register online for materials, but registering for this content online (it isn't available without registration) will be well worth it.
Here's the link to a page with a number of articles from this supplement:
http://www.bioprocessintl.com/default.asp?page=searchresults&search_type=basic&search_text=christian+julien&submit=search