There is an up to date, official mirror running on Tor as a hidden service that is still online here:

http://isax7s5yooqgelbr.onion/

I say it is "official", because the wikileaks Twitter stream mentioned it here: https://twitter.com/wikileaks/status/233859958767226880

If you don't have Tor installed at the moment, it is trivial to install it nowadays. Just install the browser bundle from here https://www.torproject.org/download/download-easy.html and you'll be viewing the Wikileaks hidden service in a couple of minutes from now.