There is a posting about Multi-Projects and Program Management in the context of Agile Program Management. The descriptions provided appear to be aimed at Theory of Constraints and the management of multiple projects, but this is not your fathers Program Management. Or even the Program Management found in domains where Program Management is a billable charge to the customer.
I've mentioned the differences between Prorgam and Project management before...
Marshall Space Flight Center's Multi Program / Project Common-Use Document is one place to look for multi-project program management processes. Others include Project Management: Systems Engineering and Project Control Processes and Requirements, JPR 7120.3, Johnson Space Center, Houston Texas, and Exploration Systems Mission Directorate: Program Management Handbook, NASA Headquarters, March 9, 2005 and finally the ever trusty NASA Systems Engineering Handbook, SP-610S, June 1995. PMI has a draft of their Program Manageemnt Guide out for review as well.
All of these have descriptions of how Program Management provides services to multiple projects, how projects can be managed as a collection - a Program, and how Systems Engineering is the basis of multiple project management, more than just collecting projects under a single moniker of Program.
All of this discussion is important because as agile process move out of the software development project with the customer in the same room as the developers, terminology already exists for these "new" terms. When the agile project management community starts repurposing these terms, those who use the terms in practice (in a possible agile manner already) get confused about what is being talking about.
There are numerous other descriptions of Program Management, ranging for education, sofwtare firms (like MSFT who has program managers) to wildlife program managers, etc. etc. etc. I woudl hope though that some common set of termonology and concepts in the Agile Project Management domain could be used - but maybe not, maybe we're in the world of he who makes up the terms controls the conversation.