The ``official'' ftp site for rec.roller-coaster is gboro.rowan.edu. The good stuff is in directory /pub/Coasters. You'll find all sorts of goodies, including images (in JPG and GIF formats), descriptions/reviews of parks and coasters, and this FAQ. Check the file Coasters.lis, which is an index of what's available.
Please limit your ftp usage to after hours, Eastern Time.
If you have anything to contribute to the FTP archive, send it to Ken Denton, sysop@elan.rowan.edu.