To start on the site, enter your Twitter name and password, find the Tweet you want to copy over, and then click the button labeled "Get @s". Pick the up arrow to get descending replies, and the down arrow to see them ascending.
Then, choose the HTML or CSS code and copy it into your post. Done. For example:
Copy. Paste. Done! That's it! Check it out at: http://twickie.pirillo.com/