XSL: Format date

Hi,

I am sure this has been discussed to death but I have not been able to
find a good source of info on it.

I have an xml:

<first>
	<date>31.12.2006</date>
</first>

I would like to convert it to 12/31/2006.

Is there any built in function for this or is string formatting the way
to go?

Thanks,
HC.