[xsl] How to URL encode?

[Brian Dunning <brian@xxxxxxxxxxxxxxxx>]

Hi - I've searched high & low on the web, but all the URL encoding 
solutions I've found are .NET or Java. I'm using PHP on some flavor of 
Linux, so I believe it's using the Libxslt library, if that's helpful.

Within my stylesheet I have:

<xsl:variable name="ItemLink" select="concat($MediaPlexURL, Link)"/>
<a 
href="http://www.anrdoezrs.net/click-1692198-5463217?loc={$ItemLink}";>

That $ItemLink needs to be URL encoded. How can I do that??

Thanks!