Make terminal use pageup/pagedown instead of shift-pageup/shift-pagedown?

I am afraid this is not possible, as no PgUp/PgDown will be sent to command-line applications, which will render some of them unusable. This is good ol' days Unix feature.

If you want more user-friendly scrolling, I suggest using the less command. It's used this way:

command-with-lot-of-output | less

This will start the less command with output of your original command. (More about piping output to other programs can be found here: http://www.dsj.net/compedge/shellbasics1.html)

Less can be navigated using arrows or PgUp/PgDown. For your convenience, it also provides searching and more (see man less for more). You can quit less by just hitting the q key.