In order to consume a web service you don't need a special license. Everything you need is included in the client networking ( runtime ).
If you want to provide a web service in OpenEdge you need the AppServer license ( which also includes WebSpeed ). The AppServer licenses includes everything you need ( The classic AppServer with the WebService Adapter or the Pacific AppServer ).
You could also roll your own Java code that accesses the database directly via JDBC of course - but I would not advise you to do that.
Heavy Regards, RealHeavyDude.