Go to http://archive.ph, paste the original URL into the input box, and click "save". You'll be redirected to the archived page, and can copy the archive's URL from your browser's address bar.
If the article has been previously saved, this will happen quickly. If not, you'll need to wait in a queue for the article to be archived.
If the article has been previously saved, this will happen quickly. If not, you'll need to wait in a queue for the article to be archived.