62957 Quick compare-two-fields scrip

I need to do a quick comparison of two e-mail entry fields. Essentially I need to catch typos and if any difference is found, ask the user to please check their email address and make sure they have put it in accurately. As long as we're doing that I'd also like to make sure it is a correctly formatted address, that is, something[at][login to view URL] or aaa-aaa[at]asdfkj.asdfas.casd.com.