I plan to use XML/XSLT in my iPhone application.
What version of XSLT is currently supported on the iPhone? Can I use XSLT 2.0 or just 1.0 ?
You cannot use libxslt on the iPhone even if you compile it and build it yourself. I have done that and have had my app rejected repeatedly. The tools used by the AppReview process do not distinguish between statically linked symbols in your code and dynamically linked symbols from the iOS. In other words, if it looks like you are using libxslt, your app will get rejected because the appstore cannot tell if you are using a private API.