This has happened to most of us. Do a search on this BBS for clutch master cylinder and you'll get a lot of hits. Try this thread for my write-up (about half way down the thread).
http://forums.pelicanparts.com/showthread.php?threadid=66282&highlight=Clutch+master+cylinder
The minimum parts list is a new master cylinder and a new bottle of brake fluid. I suggest you look at the reservior-to-cylinder tube and the master-to-slave cylinder tube and make sure they are in good condition. Replace them if necessary at the same time. I also strongly suggest that you replace the slave cylinder now. Generally, if one fails then the other will within a year. My slave died 5 months after the master. It'll take about an hour extra to change the slave with the master or 2 hours to do it in 6 months from now. Bleed the system once or twice.
The fix is not difficult. In fact, it is about the most straight-forward fix I've done on my 944 yet. Although, it could be a bit of a knuckle dinger. I suggest you find a friend with a warm garage, especially if you are going to do the slave cylinder (you need to be on your back under the car for it).