As mentioned in a previous post, the Freedom to Read Foundation is a national promotional partner of Banned Websites Awareness Day, sponsored by AASL. The issue of filtering in schools and libraries is a contentious one, and several cases have been - or are in the process of being - litigated in the courts. FTRF will continue to be involved in the issue of filters, which continue to prevent access to important information.
AASL has a good list of resources to learn more about how filtering affects teachers' and librarians' ability to educate and provide resources to students (and themselves!)
FTRF general counsel Theresa Chmara issued this July 2012 memorandum on filtering, discussing some of the most recent legal cases and their implications for schools and libraries
KQED put together a number of excellent resources on "What To Do If Your School Bans a Useful Website"
AASL member Michelle Luhtala presented a webinar last month at edWeb.net - the recording is freely available - and also recorded this radio interview