I agree it has a better case than Cannabis, much better in fact. Especially now because there have been no emergency room visits, deaths or anything...unless of course you believe that that kid committed suicide because of a plant that has been shown to act as an anti-depressant.
Here are a few organizations I know of:
http://stopthedrugwar.org/ - they just try to make all drug laws more human, I don't know if they focus on Salvia at all
http://www.cognitiveliberty.org/drug_policy/salvia_defense_fund.htm - this place has a campaign to defend Salvia.
At this point it will be difficult to get that law revoked, but it may be possible. You can try to start a local campaign and try to get a number of signatures to an initiative to overturn the legislation.
Welcome to Salvia Source!