Get rid of auto-reply message?

that depends on how you've set up this message in the first place. what did you do?

how exactly did you set up the auto-reply message? did you do it on the mail server? in that case you'll have to cancel it on the mail server as well.

If you are talking Mail, then the only way I would now how you did it was to set up a rule.
Open Preferences>Rules, and disable the auto-reply rule (i.e. deselect Active).

as Barney said the only way to do it from Mail is by setting up a rule in Mail preferences->Rules to auto-reply to everything. also, most email providers let you set up auto-reply messages on the server. You'd have to do it from webmail interface in your browser. who is the email provider for the account in question?

Go to the apple mobile me mail webpage if it is .mac mail and change the preferences there as that has the auto reply function whereas the desktop Mail program does not. There you can get rid of the auto-reply.