Ismael Ghalimi has put it in a nutshell:
BPM is Soaps Killer Application
- BPM or Business Process Management , is the art / science of capturing what your staff actually do in an IT system (and hopefully help them do their job better in the process).
- SOA or Service Orientated Architecture is designing your system as a set of endpoints (e.g. Login, get bank balance, transfer money, logout). Most systems already have this functionality, although maybe not clearly laid out.
Ismael goes into more detail , but the idea is that BPM (think Visio Diagram) allows you to draw your workflow. Each step on the workflow is carried out put an action / endpoint provided by some system (using the SOA type design).
Paul Browne 