Logic studio was the main reason for buying a new pc with osx compatible hardware (i could buy an imac for 600 euros more duh).
This is not a very detailed howto and i am sorry about that. i am not the type who keeps notes about everything he does but anyway, see it as a story which *could* help you.
you must have the logic studio.dmg
Story 1)
My old laptop acer wlmi 5102 with tapco usb link audio interface as an audio card.
I installed jas 10.4.8.
The logic.dmg on tiger complained about all sorts of things (my video card didn't have qe/ci, itunes was old etc).
I installed the new proappupdate 4.5 with pacifist. then i used the same program to install the logic.dmg
Everything was installed ok (it had a few crc errors on some wavs but not important).
For apple loops you must drag the two folders with apple loops in the program. the first one is in / and the second one xmmm i think it's in /library i think (i'm with vista now).
Story 2 and more important
Leopard 10.5.2 kalyway. first of all, leo4allv3 has a very weird bug and my sound card does not function after a clean install.
kalyway works fine.
If you can, install logic normally. if you can't read on
install with pacifist. then if it works good. but i had a problem with application crashing when it told me to select an audio interface. this was solved by installing with the normal installer of logic on top of the old installation.
To summarize:
1)install with pacifist.
2)install again with the normal installer of the dmg which will exit with error at some point but fix the previous installation.
magic
aris