Question: Learning about SOA. Is it mostly decoupling by way of web services, one service provides web services to another, thereby staying decoupled and encapsulated? Thanks.

edit: that and maybe a good front end to them like some MVC design?

Answer: 
SOA is commonly implemented using web services but can be implemented using any method of decoupling the service implementation from the interface. These are then often presented to the business in a directory when apps can request details for any service provision that offers the desired service criteria.

MVC is a pattern for applications that could access SOA but I would use the best pattern for your application rather than trying to shoehorn into a single pattern. Just remember that SOA calls are likely to be operated asynchronously.
Here's an answer I provided to another question a while ago which may help with SOA principles: [Rebuild N-tier app into Service-Oriented Architecture (SOA)?](https://stackoverflow.com/questions/2349352/rebuild-n-tier-app-into-service-oriented-architecture-soa/2366496#2366496)

Also the following is an intro to SOA: <http://www.ibm.com/developerworks/library/ws-soa-design1/>

In short there's a lot more to it than just web-services, its how you make available coarse grained 'business services' for reuse by multiple systems, and how you then make calls across multiple business services to meet wider business processes.

Developing some web-services != SOA