I've recently updated OperaORB. It has now a 'native'-mode. It means OperaORB 
runs on RMT (not SOAP). Since RMT is a Squeak specific messaging layer, it is 
not portable. But the strong point is its performance. Plese see the doc:

    * SimplePerformance comparison with rST.

Download:

    * Opera ORB 0.7-native (RMT wrapper only) - I'll also add SOAP wrapper 
    integrated.

    * OperaORB 0.6 (SOAP wrapper only)

OperaORB Examples:

OperaORB provides very simple API for distributed computing.
Server side:

Suppose you have 'OperaPerson', which is normal Smalltalk class (no special 
code for distributed object).

To export an OperaPerson:

" 1: start OperaORB (optional - normally StartUpList will do automatically)"
     OperaORB run.

" 2: init object adapter"
     OperaORB root initialize.

" 3: register object implementation"
     OperaORB root at: #John put: OperaPerson new.

Now, the OperaPerson instance can be accessed by the name of #John.
Client side:

Suppose you would like to send message #doSomething: to #John, who is waiting 
at the host named 'nowhereland'.

To send a remote message:

" 1: start OperaORB (if not started)"
     OperaORB run.

" 2: create remote object"

     john := OperaRemoteObject name: #John host: 'nowhereland'.
    "john := OperaRemoteObject named: #John." "shortcut for localhost"

" 3: remote message send"
     john doSomething: 'Smalltalk!!'.

That's all!