Email on reboot

[Bart Silverstrim]

Is there a best-practices recommended way to have a 7.04 ubuntu server 
email a specific address if it reboots or is restarted?  Emailing output 
from dmesg or a system log at boot time would be nice, but as long as 
there was some notification of the restart with a timestamp it would be 
useful.  I know there's fifty ways to do it, but I wondered what people 
found to be the easiest and "best" way to do it.