DC's school went into Special Measures last Christmas. A new head had started that Sept (so 2011), was heading in right direction but hadn't had enough time to sort things out.
It was absolutely the best thing for the children though very hard for staff I think. Lots of changes, staff leaving, lots of observations, Ofsted coming in 3 times in under a year, raising of expectations, etc. We were paired with a local 'Outstanding' school and staff came in to support our staff. Governing body were also 'sidelined' in favour of an 'Interim Executive Board'.
DD (Yr 5 now) has REALLY benefited as her year group are an 'interesting one'. DS (now Yr2) hasn't been affected as much as he has a lovely year group and has had fabulous teachers.
Education standards have risen A LOT and lots of interesting things are happening to make learning fun.
They came out of Special Measures just before this Christmas (very quick I have been lead to believe) and are still heading upwards 
Best thing to have happened to the school in my opinion though having a very driven head has helped.
Definitely speak to the new head and express your concerns and, as Hecate says, you will have amble opportunity if the school does go into Special Measures as each inspection comes with a parental questionnaire - I filled 3 sides of A4 for DD and 2 paragraphs for DS on the first one as their experiences were so different :)
If you have any questions I'm more than happy to try and answer them from a parent's point of view.