If you mean monitor all of them, I have used Ipswitchs WhatsUp network monitor to keep track of all my clients and servers. It uses many different protocols to collect data and to check for availability, from ICMP, SNMP, up to and including Kerberos. It does however cost a bit of money, but it's well worth it if you use it correctly.
No, I noticed it, but you don't have to say it's a double post in each thread, I'm pretty sure people can see that. Go outside and make some friends, kay?