firstly thank god that there are other sane parents out there who see these awful awful systems for what they are!
Definitely get in touch with www.leavethemkidsalone.com
and have a good look on the website - it offers loads of practical information and also makes you realise that you are not alone in standing against the implementation of these systems.
I faced the same problems as you (and still do) it is disgraceful that parents are given very little (no) time to voice their objections and are usually ignored if they do try to object.
There are a number of things that you can do immediately -
are they offering swipe cards or pin numbers as an alternative to the fingerprint? My children's school does (although that is still not good enough in my opinion, but it will suffice for now.) If not then start pushing for that or demand that your child is still allowed to use cash. NO CHILD must miss out on the opportunity to have a hot meal at lunchtime because of these systems and the schools know this.
After that it all depends on how obstinate you want to be. Personally I will not stop campaigning against these systems until the biometric option is totally removed from the school. To do that, you really have to be in it for the long haul - but then isn't our children's freedom worth it?
I have had a number of articles in the local press which have helped to illuminate this issue to people who had not really considered the full implications of giving away their children's sensitive biometric data, and have written to every man, his dog and his uncle's best friends!
I would be happy to help you with this or share any information that I have already gathered - you can contact me at firstname.lastname@example.org
Also I have been speaking regularly with Pippa King - her blog pippaking.blogspot.com is also a brilliant source of information.
Good luck with your campaign, let us know how you get on, and don't take no for an answer...