Two problem areas where the saxo leaks water is the airal - remove the interior light (just pop's out from one courner) then undo the nut, put some sealent under the base of the airal and then simply do it back up job done!
As for the other leak sometime when you open the sunroof the rubber seal can pop out of its trench as it doesnt seem to be glued in, and when you shut the sunroof the seal isnt pushed back into place ergo letting water in, simply push the seal back into place and its job done, you could always try and use some kind of sealent or glue to stick the seal in place but if whenever you open the sunroof you check that the seal is alrite before locking the car up you should be ok :-)
That was a public service anoucement provided by VTS_16v_Boy in conjuction with Saxperience