[37prime]

I have one domain still registered under Go Daddy. It was originally registered through Google Apps, which at that time only offered Go Daddy as their "partner" Domain Registrar.

Currently Google offer eNom, inc. as the alternative to Go Daddy, which I'm not too fond of.

I'd like to move this one domain to another registrar without causing troubles to my Google App service.

[nickcharlton]

As long as your DNS settings are correct when it's transferred, you won't have a problem.

Most registrars and DNS providers also have a checkbox to auto fill out Google Apps details. I know name.com and PowerDNS do.