You can get EZMacros and set up a macro really easilly. Just do a record keyboard and mouse buttons and set it to loop forever.

(With unregistered, it'll only loop like 50 times. This in mind, if you want it to run all night... say 8 hours... you'll have to click record and vote, then click vote again, then click vote, then click vote again, ...etc for 9.6 minutes then click run.)

Anyhow, here's a link:
http://www.americansys.com/ezmacros.htm

Btw, I voted 5 times for ya.

What is it they say about silence being golden?