Mars turned retrograde on 15th November 2007, today in Australia. When a planet it retrograde, it appears to be going backward in the sky. It’s not though in reality. Mars is retrograde every 20 months. There is a fairly comprehensive article about this phenomena here and here.
If you would like to know how this could affect your sign, Kelly Suartes monthly horoscope, provides some indications.
I personally felt a drop in energy today, may have been due to lovely warmth of the day though.