I agree with 480. Check locally. It is very important to note that if you are talking about the new lead laws, Renovation, repair, paint, (RRP) this is not lead abatement.
Here in MA I have only heard rumors. One is some locales are not issuing permits unless you are certified. Again only a rumor. i know for sure there are some that are doing nothing with the law as of yet. I also know there is legislation in the works to provide a statewide program of rules and enforcement that will have to be approved by the EPA. There are a few states that have already completed this process.
All that said, anybody that is not certified at this point and is working in a dwelling that was built pre '78 you are in violation of the law and the potential trouble you might face is very deep. By deep I mean expensive!