If you have a RedHat system it's worth knowing about rpms for this issue. A great place to start for information about that is "man rpm". But the most important commands for your questions are...
rpm -qi <package> // Tells you what the package is for.
rpm -ql <package> // Tells you what files are in the package
rpm -qf <file> // Tells you what package a file belongs to
rpm -qR <package> // Tells you what other packages this package need.
As for scripts (I guess you mean tarballs, .tgz, tar.gz), they're generally installed to somewhere like /usr/local/bin. You can check this by unpacking them and looking.
gunzip <file> // Uncompresses the tarball
tar -tvf <file> // Lists the files in the tarball
Usually the files will be installation scripts rather than the program itself and almost always, there's a file called something like README. If you look at that file, it will tell you more about where the program (and all it's associated files) will be installed. It will also tell you what you might have to do to configure it, and how to uninstall it.
As for clearing up files and links, I'd be careful about that. You can probably delete anything under /usr/local, or /opt without doing much damage, but I'd leave anything under any of the other top level directories alone, unless you know what it is and what it's for.
Bearing the above in mind, to get rid of realplayer and mplayer, just find them and delete them.
locate -u
locate -i realplayer
It won't hurt to look for readme files first
locate -i realplay | grep -i readme
John
