Here's my story about Web Services and WSE that I gave to a Visual Basic User Group in Manchester last night:

• SOAP is a way of communicating over internet friendly protocols
• Web Services is based on simple standards that made it easy to get companies to commit to the standard.
• There were many gaps in the initial Web Service building blocks.  Now there are many specifications that plug the gap - the key is making it easy for developers and developer tools to adopt these specifications.
• WSE is the implementation of many of these emerging specifications.
• WSE makes it easy to secure web services without having to secure the wire through:
  • Encryption
  • Signing
  • Exchanging security tokens.
• WSE also shows some interesting new approaches:
  • Using policies.  Allows administrators or others to apply security settings without having to recompile code.
  • Addressing.  Introduces the idea of routing web services, allows developers to virtualise the network.
• The programming model may change in future, but it's likely that the XML on the wire will change less.
  • Luckily the programming model is relatively simple.

I also recommend Werner Vogel's article Web Services are NOT Distributed Objects.