need help in planning a roadtrip from pennsylvania to south carolina. what site is best?>
What do you mean?
Are you looking for trip planning software? This site has quite a bit of information that reviews different options -- take a look at Getting Started under the Road Trip Planning section for some ideas. I bought MS Streets and Trips on the recommendation of other people that post on this site and have been very happy with it -- it is easy to use and fairly capable. While the retail price before any rebates is over $40, you can sometimes find last year's edition for much less. I got my copy (2003 edition) for about $15.
If your needs are simple, you can use a basic trip planner on Rand Mcnally's website at no charge, although it is very limited and only allows up to 10 waypoints.