Nick Malik has a must-read series at Inside Architecture. Malik is an enterprise architect for Microsoft, and his blog tends to target that audience, but his recent series offers insight for anyone heading up an SOA implementation.
I'm going to try to sum up something very complex here, but basically Malik's expounding on a research theory outlined in "Enterprise Architecture as Strategy." The idea is that your enterprise architecture model should be based upon what type of business you -- as an IT division -- are serving. There are four types of business models, and you would need to figure out which best describes your organization:
Malik's made diagrams demonstrating how these models function from an IT perspective, and he explains how to read the models here.
Malik looked at each of the four models and determined SOA would function differently in each type of organization. Not only would you need to approach building it and funding differently in, say, an organization that shares all information with centralized IT (unification model) versus a very siloed organization with separate IT initiatives (republication operating model) -- but you'll also find it's impacts vary according to your organizational type.
He's finished writing the Coordination, Republication Operating and Unification models, leaving only the Diversification model and a planned wrap-up post, "Commonality and Variability in SOA by Operating Model." He plans to link to new posts the introduction article as he writes them, so these may be finished by the time you read this post.
There's been a bit of variation in what's covered as the series has evolved -- for instance, Malik didn't break out the last two topics in the Coordination Model -- but he generally addresses the following points:
Even though the series is not finished, it's a fascinating theory and well worth your time -- particularly if your organization follows one of the already-written models.