In which regions is this service available? 

The Business Rules service can be provisioned in the United States (Dallas), the United Kingdom (London) and in Australia (Sydney). In any case, business rules can be consumed for any location worldwide.

Can I get started for free ?

Yes. This service is charged per invoked decisions, through REST API calls. It's free, up to 1000 calls per month.

How can I specify rules interactively ?

The Business Rules service comes with 2 ways for specifying rules. The first is Rules Designer, an Eclipse-based modeling environment. The second is Decision Composer, a web-based modelling tool, working in the cloud.

Can I run multiple applications in the same service instance ?

Yes. An application can contain many rules and many versions of the same rule. And the service can contain many applications.

How do you manage versions of decisions ?

Each rule has its own version number. You can invoke a particular version, or you can generically invoke the latest version.

Is this service compatible with Operational Decision Manager ?

Yes. Rules created with a recent version of ODM can be deployed to the Business Rules service for instant execution.