So this guy, Michel Gauquelin, came up with some statistics that seemed to prove there to be some actual scientific basis for astrology, in that there was a significant correleation between times of birth and levels of success in certain occupations. His work can be accessed quite widely on the Internet, but if you want to know more, start with the Wikipedia Page on him.
Now, I'm thinking, when he did his studies, it was hampered by his not having access to the computer facilities that are now easily available to everyone. It'd be interesting to use these facilities to do a new study of a much wider sample, and also to see how it correlates with MBTI type.
Before I go on, I must say that I'm not a believer in astrology. I'm open-minded, I mean, about the personality part of it (skeptical though cos I'm a very non-typical Pisces), but I totally do not believe it can predict the future.
The first major spanner in the works of this that I can think of is that I remember reading somewhere that there has been a significant increase in the number of non-natural births (caesarean sections, inducements, accelerated deliveries by means of hormone drips, etc), meaning that it might be necessary to separately research those who were born with no medical intervention as regards the time of their birth, and those who were not, compare the two and see if there's any difference.