Security alert to Hotmail users

It seems some Hotmail email accounts were recently hijacked by someone who wants to promote www.happyhu.com as an iPhone 3G vendor. I keep receiving an email from my former landlord in London (whom I haven't been in contact for long) with the following content:

Hey How are you these days? I bought one apple iphone 3gs black from this website www.happyhu.com ..

It's obvious that this is a spam. But it's hard to mark it as a spam, because all the messages from this person (whom you do know) will then be marked as spam.

I google this message content, and I found this person and this person facing the same problem.