Monitoring which of a list of machines is up

[Bijan Soleymani <bijan@psq.com>]

Hi,

I want to monitor a half dozen machines and have a screen with a green 
dot for those that are up and a red dot for those that are down. For 
this it's enough that they're responding to pings. Half the machines are 
Linux half are not.

Any suggestions?

Bijan