Following on from what Bluelion has said normally the configure script will be in the root of the directory where you have extracted the files, so in his example webcam.
Running ls in the directory should then allow you to see it. The normal process is to run:
./configure
make
make install
Note that this may vary by package and there maybe a readme file in the directory giving you details on what to do. Note to that these commands will need probably be run as root and that you will need the various build tools, e.g. make and gcc, and possibly even kernel sources (for headers) installed.