Ahhh, we'll be a happy friendly bunch when you get to the specifics of it all, it's just there isn't much to say about installing the OS, unless your thinking about partitioning drives etc.
Oh yeah, If you get Jaguar (OSx 10.2) and use it straight out of the box it may not be the newest version (depending how old your copy is) it's been updated fairly frequently and is now on 10.2.6. Just let the software update run, or pop over to Apple Support to download the latest versions.
Not sure if they're still doing it but not so long ago you could get disks of OS 9.2 for free if you'd upgraded to OS X (well £14.99).
On the subject of OS 9. Will you be running any OS 9 only applications on your mac? If you want to run them through classic on OS X, you'll have to install a version of OS 9 on your computer somewhere (hense the above mention). I use it on a seperate partition but that isn't nessacery so long as it's there somewhere.
I found the Apple forums, knowledge base and BBS to be a great help on a lot of OS issues.
Was that more like what you were after or did I go too far ?
