So its official. MSN has a posting on its blog about the outage
It seems that the speller function made it crash. Here is the quote from MSN Blog:
"We are still troubleshooting the cause of the failure at this time, and to assist us in that we have disabled the speller function of Search. Once we are done, that functionality will be restored"
Basically they will have a service pack being developed for MSN Search too!