I'm a Capricorn, and I have been a member of an International skeptics society since 2003, so as you might imagine by now, then I'm not the greatest fan of astrology. Many of my friends have been banned from astrology forums worldwide.
I'll throw in my 2 cents.
First of all, you can carry out a rather easy experiment to verify the merits of astrology. What you do, is to take yesterdays daily newspaper horoscopes (for instance), and then you mix them up. Make the Taurus the Scorpio, the Capricorn the Cancer etc. etc., then you make someone else read the (rigged) horoscopes to someone who believes in astrology, both should be unaware of the rigged status in order to double-blind test it. And the "victim" and the reader should also be believers in astrology, yet not scholars on the subject - otherwise they'll might be able to spot that the characteristics belong to another zodiac sign. The result is that people will nod knowingly while being exposed to a wrong horoscope - I have seen it many times. This is confirmation bias at large, also known as the
Forer effect, which is closely related to
pareidolia.
Here's a funny article on astrology written by a good friend of mine who is highly unpopular among the Danish astrologers. He lives undercover as he has been threatened several times by business astrologers et al. Yes, it's way out there.
Anyway, I once made a small program where you choose among several characteristics that you think is related best to your personality, 12 times. Then the program shows you how many percentage of each zodiac sign you are. This is called reversed astrology =)
I don't hope I offended anyone with this post, that wasn't the intention, but a subject was brought up that I know a little bit about, so I jumped in =)