How do I ....

ok, I'm starting to play with sessions and have a few things I want to do, first is recompile --with-trans-sid and I'm pretty sure I know how to do that (make clean, then configure, etc.) However, I'm thinking of changing a few of the things <? phpinfo() ?> is giving me like: session.use_cookie and/or session.save_path or anything else they list there. My question.. how do you do it? Thanks Mike