Salzburg - getting from the airport to the Sheraton - You can catch a bus from the airport to the main train station (cost is 1-2 euros - can't remember exact fare but it wasn't much - probably a 20 min ride). From the hbf, it is a 10-12 min walk - doable if you don't have too much luggage. If not, you can catch a bus going towards the river and ask the driver where to get off.
Vienna - from the main train station to the Bristol - If memory serves me right - the U-bahn drops you right at the Bristol (across the street depending on which exit you take). I think there is a change of lines involved. You can easily check this by finding the website and following the lines.
I believe the rough cost for a 2nd class ticket between Salzburg and VIE is between 20-30$. First class is probaly 50% more.
[This message has been edited by acnev (edited 04-15-2003).]