Put quite simply, there is no future for Office Web Components (OWC) going forward. Microsoft has decided not to update OWC beyond the current version (OWC v11) included Microsoft Office 2003. While they will ship with Project Server 2007, they won't ship in the 2007 Microsoft Office System (clients or MOSS). If you're currently using OWC in your solutions, no fear... they will fall under the same support model as other discontinued products (for example, OWC v11 is supported through 2011).
It boils down to the fact Microsoft needed something that would provide more flexibility, improved security, and added features. Microsoft is achieving these requirements with Excel Services, a piece of MOSS (available via Enterprise CALs), which essentially provides server-based Excel spreadsheets and a server-based calculation engine.
I fielded two questions about the future of OWC when I was working the Office TLC "ask the experts" area at TechEd 2006 in Boston earlier last month. When the questions came up, I hadn't even thought about OWC WRT to the 2007 release... after asking around, it seemed most people weren't so I thought it was safe to say "I'm sure they are getting updated... but don't consider that an authoritative statement." Ends up I was dead wrong but I have no way of contacting the two people who asked me about them (never caught their names). This is my only venue to resolve my error... so here you go!