JMS performance.

Hello folks,
I need to make an application, that is very much like a chat application.
There would be a very big chat room with all the members (some kind of publish/subscribe, where all the peers could be submitters and listeners) and there will be a lot of PM chats, some kind of point to point messaging via the server.
The protocol needs to be light (not very verbose, after all we just need to send a message by identifying the destiator).
My question is: is JMS suitable for this kind of applications or is it too "heavy" for this purpose? I have read some time ago about XMLBlaster which provides TCP /RMI / SOAP/ CORBA and many interfaces to a messaging bus based on XML, and there were a performance page stating that for 10.000 clients (subscribers) and a publisher; With CORBA, 435 messages/sec are delivered on a 600Mhz pc.

Is there a better performing messaging BUS (open source / free )? And how does it compare to JMS performance ?
Shoot!
Thanks in advance!

why do you have to go with JMS CORBA and stuff why not develop it using JSP and servlets

http://www10.brinkster.com/ssruprai/demo/jsp_chat.asp

Thanks for the reply Kripal

Well I said it looks like a chat room ( the design) but it is not a chat room

So jsp is not an option. I need to have a messaging bus for java clients (like aplets) and where peert to peer communication is not an option. (everything has to go through the server)
Any ideas? JMS performance in general for 10.000 clients subscribed to a listener? Does JMS perform better in point to point messaging or in publish subscribe?
There are some papers on the net, but not that practical.