usually I install stuff from rpms, so I'm not 100% sure about how installing from source works. I know how to do it, but not the mechanics behind.

For arguement's sake let's say I have program a that I am installing from source. I place it into a directory called program a. Then I run the usual ./configure make make install. I don't use any special flags or options, just those three commands. Where is the file installed? More importantly, is it installed in the folder program a?

Or, to clarify, can I safely delete folder program a after installing or is the installation now sitting in that folder?

Try this thread, and the associated artile.
I'm sure a search will turn up more info.

cool, seems to be yes. q) Saving me lots of space on my hda

you always at least want to do ./configure --help to see what options you have, ./configure make make install will only get you so far. also note that with libraries, often you will need to pass some things to configure, especially if you have an older version of the library on your system.