I think your best bet would be to look into accredited Bachelor programs in Forensic Science. WVU and Penn State have really great programs - At WVU you can even specialize in forensic investigation. You will have to take coursework in biology and chemistry, however. What is nice about having this degree is that you can do crime scene investigation (work in the field) or work in the lab as a forensic scientist. Also, the International Association for Identification (IAI) website is helpful when looking at jobs, training, and certificate requirements.
If you do not want to get a degree, you could probably start out at an entry level position being an evidence technician and work your way into doing CSI work. However, you will not make much money. Also, the CSI position in Pittsburgh requires a bachelors degree and is pretty competitive. Hope this helps.