XSLT for device-dependent user interfaces

Hi, I'm completely new to XSLT and still getting a feel for exactly what
it does.

Would XSLT be useful in the following use case:

A web application serves a user interface as a generic XML file which
formally describes buttons, fields, menus, tables of data etc. but not
how they should be presented. Two users both wish to use the web
application but one is using a laptop computer and one is using a mobile
phone with WAP or GPRS. XSLT is then used to generate two different user
interfaces from the XML output of the web application, an XHTML
representation and a WML representation of the same interface, each
suited to its own platform.

Where exactly is XSLT implemented? I see that there are implementations
in server-side languages but I've also read that XSLT is built into some
web browsers and Google has recently open-sourced a JavaScript
implementation.

Thanks for your help

Ben "tola" Francis