Line breaks in transformed XML

I'm using oXygen to convert and XML document to a newer XML spec for my
application. I'm writing an XSL transform to go from the older version to
the newer version of the XML spec, but when I apply the transform to the
older version, and get the output, it's all on one line. I'm not sure how to
insert line breaks via my transform, so that the resulting output is all
nice and indented.

Any suggestions?

Jon