"The campaigners from the threatened schools were linked up by one Internet savvy parent (in a non-threatened school I recollect)"
If that's who I think you mean they used this to do some of the co-ordinating.
There had already been people - including pupils - making use of (the relatively new) 'social media' (inc MySpace and Bebo!).
"Most were then closed one by one but at least one was reprieved."
Some have been closed - and at least two demolished. All three 'threatened' secondaries are still open (Castlebrae reprieved again very recently).
One of the closed schools - Bonnington - is being refurbished (at a much greater cost than if it hadn't been empty for years...) as the Gaelic school.
My theory has always been that Education officials went to the fairly new (LibDem) councillors and said 'we need to save money and shut all these schools'. But their list was deliberately long as they assumed councillors would say 'oh no you can't shut that one' (several times).
But those 'in control' just said 'OK'. Same people were running the tram at the crucial period.
"I think SRD's idea about parents across Edinburgh with an interest in cycling is a winner."
"Not sure how much more would be needed initially than something like this forum coming up with stock proposal to take to each parent council"
I think that would be a start and a mechanism.
Over the years I have encouraged/helped parents set up "Safe Routes Groups". Since then I have worked more directly with (a few) schools and had no contact with parent councils.
Last year I created CyclingSchools.info in connection with some work I was doing for CEC but not part of that work. Basically a collection of 'useful things', in one place, that I could show pupils and teachers.
Expanding this with more info about individual schools and stuff for parents and school councils would be easy...