RAR is a compression format, http://en.wikipedia.org/wiki/RAR, and the files you have are compressed archives of one or more original files. First, you have to decompress the RAR archives. Here are some utilities that can do that
7-Zip (Free, Windows) http://download.cnet.com/7-Zip/3000-2250_4-10045185.html?tag=mncol;1
WinRAR (Shareware, Windows) http://download.cnet.com/WinRAR-32-bit/3000-2250_4-10007677.html
Stuffit Expander (Free, Mac http://www.stuffit.com/mac-expander.html, Windows http://www.stuffit.com/win-expander.html)
The Mac OSX comes with Stuffit Expander.
UnArchiver (free, Mac, Linux) http://wakaba.c3.cx/s/apps/unarchiver.html
If you have a series of RAR files that are names in numeric sequence, it means that the archive was very large and has been broken up into smaller pieces. First, put all of the files in a folder together. Then you can highlight all of them and extract them with your RAR expansion utility, or select the one named filename0.rar and the utility should be able to recombine it with all the others.
After that, how you use them it depends what type of files you have once the archives are uncompressed.