Just a simple question.Actually,I googled about this but didn't get a well answer.All were explaing about how to install and using a specific options,etc,etc.

So,here's the question:

If you want to install a package which is in source code(tar.gz or tar.bz2) and yes you installed it by using "./configure", "make" and "make install" or by other method by going through the respective package's README or INSTALL file.But in future if you want to remove/uninstall that particular package then how will you do that?
For .deb or .rpm,you can use rpm or dpkg command along with some option to remove the package and in Slackware,there is removepkg or slackpkg remove ------ or can use pkgtool to remove package.
I installed php from its source code and configure with this command
and now want to remove php without making any changes to mysql and apache in Slackware 13.37

Usually, a source Makefile will include an uninstall target. So just go to the source directory and:
If there's no uninstall, I usually rerun the 'make install', note the installs, then remove them manually.

Is it good idea to keep extracted folder after you have done with installation?I mean after you have run "make install".If yes,then I don't know about this and usually what I am doing is "rm -rf extracted_package_name".

Source directory means frsh extracted tar.gx package or the content of the directory after you have run ./configure,make and make install commands.

Yes, either keep the extracted source directory, or re-download it when you want to remove the packages. This is why using a package manager (rpm, dpkg) makes life easier.