The only way to do it would be to include long URLs in parenthisis after certain words, but when I tried that it looked really messy - almost unreadable.
Still, that was only the first attempt; I'll mess with the format as time goes by and try to come up with the best way to do it. If people have suggestions (such as this one), I'm all ears.
it is possible to send an email that is formatted for both. If the recipient's email program can read HTML email, they see that, if the email program cannot, the text only shows up first.