OMB in particular runs the gov's CIO Council which coordinates government IT throughout the executive departments by means of each department's CIO. OMB also runs the new (as of August, 2014) U.S. Digital Services.
The first is the "Digital Playbook" which describes a dozen or so "plays" (somewhat as a sports analogy of plays). But the interesting one is the "TechFar Handbook" which you can read and download from this github location.
The TechFar Handbook subtitle is: "handbook for procuring digital services using agile methods". It is structured more or less in a Q&A format, divided among sections. It takes off from the authority in FAR 39.103 which is all about modular contracting authority and procedure. It then shows the compatibility between agile and the intent of modular contracting, and it gives hints on how to "stretch"-- within the law -- to be more modular.
Sounds like it is all going in the right direction. Let's all cheer the U.S. Digital Services
Read in the library at Square Peg Consulting about these books I've written
Buy them at any online book retailer!
Read my contribution to the Flashblog