I forgot where I install firefox or a certain program, how do I find out where I installed it in Fedora 8/Linux

PROBLEM:
It's been two weeks since I install my FireFox browser, and well I forgot where I put it (not that it matters, it's working fine) But I'd like to know where.

SOLUTION:
open a terminal.
run below command:
whereis firefox
and I was shown the below:
firefox: /usr/bin/firefox /usr/lib/firefox

now I remember, I installed it in /usr/lib/ and made a link to it from /usr/bin/