this is fixed now:
Official Google Enterprise Blog: An update on encrypted web search in schools
Less than two weeks ago, we announced here that we would be moving our encrypted search service to a new hostname in order to better serve our school partners and their users. Today, we moved encrypted search from https://www.google.com to https://encrypted.google.com. The site functions in the same way. However, if school network administrators decide to block encrypted searches on https://encrypted.google.com, the blocking will no longer affect Google authenticated services like Google Apps for Education.
We are continuing to explore longer-term options such that we could return encrypted search to https://www.google.com without introducing issues with school content filters.