The last time I thought about IT 'governance' in-depth was a while back. Of course everyone claims its top of mind when thinking about SOA, since that same 'everyone' is trying to convince the business guy with the cash that the business and IT have converged, and he should spend his money on more tech stuff. And its true that if you really design meaningful services they can reflect the what the business does, which in turn enables a business leader to ensure he or she will meet the business objectives that demand a big fat bonus.
The last time I thought about IT 'governance' in-depth was prior to working on how SOA makes IT better, or beating business goals with process optimization. This was back when I concentrated on 'compliance'. In the good old days when SOX was new(-ish) and still hyped (although according to Google Trends, it never compared to the Red Sox or White Sox that dominated the sporting public's attention), I paid a lot of attention to the details of how organizations really became and remained compliant with the mass of legislation and regulation out there.
From a business standpoint it was easy - COSO was recommended by the SEC as a fine framework for documenting and testing your internal controls to ensure compliance, even though any sort of framework for defining how effectively you did business was considered radical and expensive.
IT, probably because it was always a left-brain discipline, had many frameworks that were favored and used extensively. Especially when IT was expensive and often owned only by governments or the military, minimal risk of failure (or at least the bureaucracy around CYA) was considered essential and led to the use of frameworks such as ITIL. This was intended to ensure that every phase of telecoms and technology usage, from acquisition to deployment, to eventual failure and fix was defined (if not by the framework itself, by the poor team attempting to implement and run a system).
COBIT on the other hand offered an apparently focused approach to IT governance, since it limited its scope to IT controls - the automated bits of business worried about maintaining systems to perform consistent decisions. The problem with all this was that most organizations already had some form of adopted framework. SOX compliance for IT often became a 600 page bound work of photocopies from other frameworks, printed screenshots, and a little summary of the true processes that the IT organization followed in putting new systems into production.
In reality, what IT framework do most organizations use? And how well does this tie back to the emerging governance requirements of SOA? What does the outside world do? And how does this vary between financial services organizations, government, software or others? People are core and their consistent and effective communication is as important as any framework. Without good people, most frameworks will fail.