Alternative to KnowNow?

I was considering using KnowNow's LiveServer for a project, but the  
price is really prohibitive - so I'm looking for alternatives.  There  
doesn't seem to be too much activity on mod_pubsub, except the  
declaration that things are being rewritten.  Is there something  
usable right now that I can use where publishers and subscribers can  
be on Java platforms (Mac OS X) and .Net?

Thanks!
Ken



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