Regardless of the topic - the best path to learning is usually through hands-on experience. To read about a topic or have someone else describe it - while useful - is no replacement for getting your hands dirty. In looking at SOA this can be a challenging situation as there can be multiple development and runtime tools that need to be downloaded, installed and configured before getting started with any experiential learning (unless the goal is to learn about downloading, installing and configuring).
A useful alternative is to check out the SOA Sandbox. The SOA Sandbox is a cloud-based offering from IBM. The goal is to provide a way to get started with the SOA Entry Points and the associated set of IBM Products and Best Practices. By being cloud-based - there's no need to download any tools or runtimes (although there is a small Citrix plug-in download).
Once in the Sandbox, there are simple hands-on guided exercises. Its a great way to explore, learn and experience tools. Some of the tools available include: WebSphere Application Server, WebSphere Business Events, WebSphere Enterprise Service Bus, WebSphere Process Server, Rational Application Developer, and WebSphere sMash (here's the complete list)
The Sandbox takes things further by including access to an Information Center - which contains documentation on Best Practices and architectural guidance. This includes whitepapers, decision guides, technical presentations and demos.
The Sandbox is available 24/7 and is free. Exercise trials are available in 4 hour windows.
Seems to me, that this is a great way to learn about SOA as it reduces the typical hassles involved in getting set up - while incorporating guidance and exercises.