Cubase Lite came on my mac, and I love it! I've also got the disks for it.
A whiile back, I transfered my 800K Cubase disks to 1.4MB images-PM your email address and I'll send them if you like.
As for the hardware-all you'll need (but you probably need this for any composition software) is a MIDI interface box and a MIDI keyboard (make sure it's got built in sounds if you want to hear your music).