Thats a good one Mishy,I thought it was gonna like the one I have in my favourites but it isnt..
EDIT:
The one in my favourites isnt the same as this,this is quite handy for what I been wanting to do lately..... Heres what I have in my favourites
http://validator.w3.org/checklink
EDIT2:
Here is another editor:
www.pspad.com/en