Oslo - the latest is the next generation SOA and BPM technologies that will let Microsoft lead the way the SOA maturity space. Consist of five areas:

.NET Framework 4.0 and evolution of WCF and WF into a model driven development that allows easier services enabled processes

The next version of BizTalk Server 6 which will now build on top of WCF and WF - for example the messaging layer will be based on WCF messages not XML messages

Hosted Services - examples of early beta versions can be found in labs.BizTalk.net and this is just will get more mature and enterprise ready

Tools that manages lifecycle support and model driven design of service enabled  composite applications that will be incorporated in VS 10

Metadata repository like the one in MSE but fully integrated into the next generation of System Center so deployment, versioning   and managing these services become easier.