From the wikileak article linked below:

"Having Julian Assange elected to the Senate would give him some advantages, at the very least the embarrassment of the Australian government having to communicate to whatever authority in Sweden - or the USA as the case may be - about 'Senator Assange' or, if ensconced in Parliament, the embarrassment for Attorney General Nicola Roxon if ASIO was found to have tapped Julian Assange's parliamentary phone and internet connection."

Then it goes on about starting a wikileaks party and actually archiving some political change.