In XSLT 2.0 you can use the format-date() function, in 1.0 you'll need to use low-level string manipulation (substring, concat, etc). You might find a library routine to do it at
www.exslt.org.
Incidentally if you're going to illustrate your required format by example, then choose an example that isn't ambiguous - we can't tell whether 9/9/2005 is d/m/y or m/d/y.
Michael Kay
http://www.saxonica.com/
Author, XSLT 2.0 and XPath 2.0 Programmer's Reference