Someone asked how to send binary attachments between .NET and WebSphere.
After much wailing and gnashing of teeth, the W3C standard for sending attachments in webservices is MTOM.   On the Microsoft side, MTOM is supported in WSE 3.0 or WCF .  
I believe MTOM is not yet supported in a released version of WebSphere Application Server.   Hmmm...   You could use Apache AXIS on the Java side - AXIS 2.0 does MTOM, and it just went to the 1.0 release (not sure how the AXIS guys came up with AXIS 2.0 1.0, these version numbers are baffling to me.  But those who live in glass houses, etc etc. )  But if you rely on AXIS for MTOM in WebSphere, you've voided your warranty.  Hmmm, not so good.
I believe you will have to wait a bit longer for MTOM in WebSphere.   Maybe one of my IBM friends can comment, I will check.
In the meantime I will work up a simple example app that does AXIS 2.0 1.0 and WCF interop with MTOM. That should post soon.