We had this problem with my daughter's Toyota Camry. In each corner of the sun roof there are drains, which can get plugged up with debris, which causes the drain gutter of the sun roof to overflow...
All factory installed sunroofs that retract flush into the roof have a channel around their perimeter and there are drain tubes attached to the corners. The drain tubes run down the roof pillars and...
depending on if you can find the approximate location of the leak it is possible to fix it with some beaded silicon (available at the hardware store near paint or auto store). You will need a caulk...
Best thread I've found on this problem (and I've followed the steps and advice myself) is located at http://www.subaruoutback.org/forums/showthread.php?threadid=8005. This saved me a lot of money in...