If you are changing web hosts...
Recently, I moved from Slicehost to Linode. For one particular site, Slicehost was my name server. When I had everything working on Linode, I cancelled my Slicehost account, thinking the DNS settings on Linode would take over and my domain name would be pointing to the right place.
Well, it didn't at first...but I know DNS changes can take time. So I waited...nothing. Checked the DNS settings on Linode. Everything looked right. So I waited some more...nothing. The whois information still showed Slicehost as the name server for the domain. I started worrying that I should have changed something on the Slicehost account before deleting my account.
Finally, it dawned on me to check my domain registrar (I use Site5) and see if there were any settings there. Sure enough, that's where you can set the name servers for the domain. Changed to point to Linode's name servers, and life was good again. My sincere apologies to any of the two people who might have tried to access that site during my fit of stupidity!
