The last time I moved a domain to a new host, I changed the nameservers with the registrar, waited a day or two, then went happily to work on the new website. I didn’t notice (until the bill came) that the previous host was still charging me.
So this time, I changed the nameservers and dropped an email to the previous host telling them that I had done so. They <sarcasm>very kindly</sarcasm> suspended the web hosting service immediately, way before the nameserver change propagated. So now my users are up the creek for a day or two. It’s my own stupid fault, though.

Yer damned if you do, damned if you don’t.
That wasn’t very nice of them to cut it off like that! Putzes!
I’m feeling kind of cranky about it…but I should have waited until the domain name pointed to the new place, then written to them.
I’ve had an account with them for seven years, but they really aren’t keeping pace – they have no cgi-bin, no shell access, a 10MB web account costs $29.95 a month(!), they charge extra every month for the domain name, you get the idea. Plus, by now, that email address is 90% spam. So it’s time to give them up.