Mac OS X<->PHP setup

I just installed OS X on my G4 server but I'm a far ways from getting php to work because of my limited experience with Unix. The Apache server is running but I still have tons of questions that I'd appreciate any input on--some relating to PHP and some to Mac OS X: What kind of setup should I have? 1) I need a multi-threaded database because I'm expecting many simultaneous hits, so would you recommend PostgresSQL? 2) Also, I can't seem to find an HTML editor (TextEdit doesn't work well) to even write HTML/php files--where can I find one? 3) Once I download PHP4 (can i assume the Unix/Linux one is the one I want) do i need to configure anything in the Apache server that comes with OS X? what about setting up odbc connections? 4) There seem to be multiple versions of downloads for Unix (linux, solaris, bsd, etc.) --could someone confirm that Mac OS X is based on FreeBSD and that is the Unix type of file i should download? I'll probably think of more questions later... THANKS SO MUCH, Amelia