let g:addys = ['lewk@csh.rit.edu', 'lmacken@redhat.com', 'lmacken@fedoraproject.org']

function NextEmailAddress()

    if !exists("g:email_idx")

        let g:email_idx = 0

    endif

    s@^\(From:.*\)<.*>@\="\1<" . g:addys[g:email_idx % len(g:addys)] . ">"@

    let g:email_idx += 1

endfunction

map <silent> @ :call NextEmailAddress()<CR>