<p>I'm looking at a new computer which will probably have vista on it.  But there are so many editions of vista; are there any weird restrictions on what you can run on the various editions?  For instance you couldn't run IIS on Windows ME.  Can you still run IIS on the home editions of vista?  </p>

I would suggest: First find your k random numbers. Sort them. Then traverse both the linked list and your random numbers once.
If you somehow don't know the length of your linked list (how?), then you could grab the first k into an array, then for node r, generate a random number in [0, r), and if that is less than k, replace the rth item of the array. (Not entirely convinced that doesn't bias...)
Other than that: "If I were you, I wouldn't be starting from here." Are you sure linked list is right for your problem? Is there not a better data structure, such as a good old flat array list.