tell application "Outlook Express"
        set selContent to the selection
        if selContent /= "" then
                set NewSel to ""
                repeat with i in selContent
                        set j to ASCII number of (i as text)
                        if j >= 65 and j <= 90 then
                                set j to ((j - 52) mod 26) + 65
                        else if j >= 97 and j <= 122 then
                                set j to ((j - 84) mod 26) + 97
                        end if
                        set NewSel to (NewSel & (ASCII character j)) as text
                end repeat
                display dialog NewSel buttons {"OK", "Insert"}
                if button returned of result is "Insert" then
                        try
                                set the selection to NewSel
    -- uncomment the line below for AppleScript < MacOS9
    -- on error
                        end try
                end if
        else
                display dialog "You must select some text for this script to work."
        end if
end tell