Although we're 98% resigned to top-posting e-mails thanks to M$ setting the standard of putting the cursor above the header so long ago (as well as so many people choosing HTML as their default format), if you're a geek or wannabe geek who uses plain text format and likes to reply below the quotes (as is our standard in these forums, for example),
here is a free download you may enjoy. I've used it for years. It automatically "fixes" the headers in Outlook when you hit reply, and you can also customize them to your liking. Note that this has no effect on HTML e-mails.
Not sure many will benefit from this, but for the few that will they'll find it pretty cool.