Splitting a stirng

I have an XML document with an element whose content is a string containing
"fields" delimited by semi-colons.  Example:

	<PACKEDINFO>123;ABC;0;X</PACKEDINFO>

I want to transform this element into something that looks like this:

	<UNPACKEDINFO>
		<INFO1>123</INFO1>
		<INFO2>ABC</INFO2>
		<INFO3>0</INFO3>
		<INFO4>X</INFO4>
	</UNPACKEDINFO>

Can I do this with XSL?  I'm familiar with the substring functions and while
I've never used them, I've read the documentation on the param and variable
elements.

If I were doing this in a programming language like VB, I'd set a variable
to the contents of <PACKEDINFO>, pop off the part before the first
semi-colon, create my new element and remove the text up to and including
the first semi-colon from the string setting me up for my next iteration.

Any comments on how I can do this with XSL would be greatly appreciated.  I
guess my biggest question is whether I should use a param or variable -- I'm
having difficulty distinguishing between them -- and whether I can change a
param or variable's value by simply declaring it again.  I'm very confused.