I had a big DNS problem today and this article really helped me out very detailed and easy to understand. I have worked with DHCP and DNS in the past never realized how many setting and options there really were to set. Was interesting you would ping a PC by name and would come back with the wrong IP. The problem ended up being a combination of short DHCP leases with a long aging and scavenging time set in DNS.
http://searchwindowsserver.techtarget.com/tip/0,289483,sid68_gci1040355,00.html