There doesn't seem to be anything wrong with the server...
except the fact that I am having to restart it occasionally since our router has been playing up again..! It's only a week old and it our 7th(!) router from BT in 2 years - they always break. They are SHITE!
Make sure yr logged into minecraft and have the correct url:
http://www.minecraft.net/play.jsp?server=8b37d350982f1d7669559746f0ef1981