ValueChain is the concept first put forward by M Porter in his book called "Competitive Advantage", a few years after his best selling CompetitiveStrategy book.
From MeatBall (click on link below for more)
- The ValueChain is the chain of steps and processes a business takes to create economic value between its suppliers and its customers.
A link from WikiPedia points to this location that has more explanation. See http://www.themanager.org/Models/ValueChain.htm which talked about different types of ValueChain