I just thought I'd post here too:
I have now set up a jabber server for edugeekers, if you would like an account please pm me and I'll create one for you.
It can be accessed as a normal jabber server, or via a choice of 2 web based clients: https://wizzymail.com/xiff and https://wizzymail.com/jw
The second one is the client most likely not to be filtered.
The more people who have accounts, the more it'll be useful.