I don't know about fedora, but there is unrar in my system (debian). In case there is no unrar, you can pick one from debian sources
and compile one for you.
The uptstream site seems to be down, atleast at the moment.
To check wether you have unrar allready or not, try running 'rar' or 'unrar' and see what it says. Using them is quite straigthforward: 'unrar x foo.rar or 'rar x foo.rar' should open the package.'