If you haven't had a chance to look closely at BPEL, now might be a good time to do so. I find the concept of scripting a business process in XML to be a very attractive one. There are already several tools and runtimes available that offer BPEL support and I expect that number to grow now that BPEL is an OASIS Standard.
The following, which is taken from the Abstract section of the WS-BPEL 2.0 Specification, describes BPEL very well in a nutshell:
This document defines a language for specifyingbusiness process behavior based on Web Services. This language iscalled Web Services Business Process Execution Language(abbreviated to WS-BPEL in the rest of this document). Processes inWS-BPEL export and import functionality by using Web Serviceinterfaces exclusively.My congratulations to my colleague Diane, who co-chairs the TC, and to all of my other colleagues and the entire WS-BPEL TC on this very important achievement.
Business processes can be described in twoways. Executable business processes model actual behavior of aparticipant in a business interaction. Abstract business processesare partially specified processes that are not intended to beexecuted. An Abstract Process may hide some of the requiredconcrete operational details. Abstract Processes serve adescriptive role, with more than one possible use case, includingobservable behavior and process template. WS-BPEL is meant to beused to model the behavior of both Executable and AbstractProcesses.
WS-BPEL provides a language for thespecification of Executable and Abstract business processes. Bydoing so, it extends the Web Services interaction model and enablesit to support business transactions. WS-BPEL defines aninteroperable integration model that should facilitate theexpansion of automated process integration in both theintra-corporate and the business-to-business spaces.You can find links to the specification documents here.