I made a small collection of unit libraries across languages.  You can find it here:
<a href="http:&#x2F;&#x2F;www.diydsp.com&#x2F;index.php?title=Physical_Unit_Conversion" rel="nofollow">http:&#x2F;&#x2F;www.diydsp.com&#x2F;index.php?title=Physical_Unit_Conversi...</a>