Cluster Monitoring software?

[Joseph A Del corso]

Hello, 
	I was curious if anyone knew of a
stable software program for monitor cluster activity,
specifically cpu usage, disk activity, ethernet traffic,
etc.  I'm aware that gkrellm has this ability, but 
appears to useful only for monitoring a single 
node at a time.  I'm also aware of bWatch (beoWatch)
and have already used it in my (small) cluster; but
bWatch doesn't give the (semi) "realtime" display of
cpu load average (if I'm wrong please correct me)

Also, at ALSC I vaguely remember hearing someone mention
that there was a utility built into a webpage for 
monitoring system activity (I'd like to know how this was done).  
Could someone refresh my memory please.  

~~joe