Try this unblocker!

It's new and nobody knows about it yet:
http://tiredstudents.com/

It looks like a lot of school administrator type people have been watching our sources, and are blocking new unblockers pretty much as soon as they're released. So all the unblockers we've posted on this site are probably blocked and any new ones we post from that same source will be blocked very quickly as well. For this reason it'd be best if you try to make your own unblocker instead - you can find instructions on how to do this here: How To Make A Proxy

How you can unblock Yahoo Mail in school - Week 13, April 2010

We post a few unblocker sites roughly every week, so subscribe to our feed to stay updated!

Some advice for using unblockers for Yahoo Mail

The trick is to find an unblocker that very few people know about. This is because popular unblockers will get blocked faster. Unblockers that you find by searching the internet will be blocked quickly because they're so obvious. Even if you find a good one it would be smart to have an alternative you can use if it gets blocked.

Here are some unblockers you can use to unblock Yahoo Mail:
www.stepfree.info
playthis.co.cc
2dmovies.co.cc
talkmax.info
peoplehider.info