Yes, it's true. By 2010, the National Veterinary Technician Exam will only be taken by people who have a degree in veterinary technology from an AVMA accredited program.
Laws in most states are also changing to require education and exmaination for registration/certificat/licensure as a veterinary technician. How much will change in each state as concerns exactly what a credentialed technician can do compared to an assistant will depend on that specific state's laws, but changes are underway in many areas.
If you are already working in this field and know that you want to persue and education, I would recommend going ahead with a degree in veterinary technology. The veterinary assisting programs will not count towards a degree program so aren't really worth much in the long run. However, Cedar Valley College in texas offers a veterinary assistant certification program that does give you some credits towards a veterinary technology degree should you decide to go on with your education throught them.