I finally got around to putting something interactive on
umop-apisdn.org. It takes whatever text you enter and tries to turn it upside down. It works best with lower case text.
I used the Unicode
IPA character set which contains nearly all the upside-down characters I needed. You may find that your browser may or may not render any or all of the IPA characters, so I've provided an ASCII rendering option for backwards compatibility.
¡unɟ əʌɐH
2008-07-23T09:59:11Z