What kind of email is it? Gmail, yahoo, etc...?
I found the stock email app that Samsung has to be rather lousy. I use Aqua Mail, which is much better and I get push emails for my Gmail and rackspace accounts. Yahoo doesn't have the option to use IMAP for some reason.
Others on here use Blue mail but I haven't got any experience with it. I would strongly suggest a third party email app, though.