I wrote the memo (mostly). Here's some historical context:
In 2001-2002 (or so), the Defense Information Systems Agency was in the process of certifying RHEL as being compliant with the Common Operating Environment, which was like a DoD-version of the LSB, sorta. Rumor has it (was before my time) that a certain OS vendor (popular in the desktop space) took exception to this fact and drafted an unsolicited memo for the DoD CIO, which effectively would have banned OSS.
The DoD CIO at the time was a guy named John Stenbit. Stenbit was (and is) a strong-willed visionary, who wasn't about to roll over for anybody, so he (through DISA) commissioned a survey of how much OSS was currently in use in DoD. The study got farmed out to MITRE, specifically a guy named Terry Bollinger. The results of the study were that OSS was being used in lots of places across DoD, in some cases for mission-critical things, and interestingly extensively by the information assurance community. (e.g. snort)
So Stenbit got someone to write a new memo, which he signed in 2003. It said roughly: OSS is okay, it's just like other software, but make sure that you get approval before you use it. (Same as anything else.) Stenbit retired from gov't in 2004.
In April 2008, the Deputy CIO (Dave Wennergren) got the idea that we ought to have updated DoD guidance on Open Source Software. I believe it was suggested to him by Scott McNealy (Sun), Art Money (former DoD CIO from 1999-2001), and Bill Vass (Sun, but former gov't executive under the DoD CIO). Dave asked around if there was anybody on the CIO staff at the time who knew much about OSS. That ended up being me.
I was a CS major at MIT, class of '95; used to work down the hall from Richard Stallman. I was on ROTC scholarship and later served about 6 years as an active-duty officer. I started working as a civilian in gov't in 2002, and in 2004 I took a position with the office of DoD CIO - partially so that I'd be in the right place to advocate OSS in gov't.
Four years later, I got an golden opportunity: I got the task to figure out what the updated OSS guidance should say.
I drafted the memo, with help from lots of folks, including David Wheeler, John Scott, LtCol John Barrette, Dave Emery, Terry Bollinger, MaryAnn Kiefer, Roger Loeb, Frank Petroski, Monique Pryce, JC Herz, and probably others I forgot to mention. I briefed the concept to Wennergren. Got feedback. Revised. Sent out to other offices in the Office of the Secretary of Defense (OSD) for coordination. Sent to the Military Department CIO offices for coordination. Spent many, many hours coordinating and revising with the Office of General Counsel (OGC) for the OSD, the Army, USAF, and Dept of Navy. It was mostly done a year ago, but it kept getting held up because someone wanted to review and comment.
One paragraph in the memo is traceable to a particularly heinous licensing debacle with a particular software vendor (not Microsoft) that affected a particular software project, and could have been avoided by using OSS.
The lawyers were by far the biggest delay. I wanted to reference the Open Source Definition (published by the Open Source Initiative), but lawyers wouldn't let me, on the grounds that doing so could be considered an endorsement of a non-federal entity, which would violate the Joint Ethics Regulation. I argued that this was a ludicrous interpretation of the JER, and eviscerates the authority granted to the CIO by the Clinger-Cohen Act. But after months of no-progress, I compromised and the final memo does not reference the OSI.
There was no direct involvement by the White House for the 2009 memo, and I don't think for the 2003 memo either. The generally favorable attitude from the current administration toward "openness" meant that I (and I think Mr. Wennergren) felt a pro-open memo would be well received, but we didn't consult with the WH, nor does the WH get that deep into agency policy - even for an agency as big as DoD. If the WH wanted to push policy on OSS, they'd do it through OMB for the whole executive branch. There was a rumor for a while that the WH might pick a former Microsoft exec as the DoD CIO, which might have scuttled the effort, but that hasn't happened.
Mr Wennergren is giving the morning keynote at GOSCON on 5 Nov 09, and I anticipate he'll talk a bit about the memo.