Apologies if this is common knowledge but I couldn't find this on a quick search of the peripherals forum...
I just bought a LaCie 16x10x32 Firewire CD-Writer for my iBook and was impressed by the fact that it could burn from the Finder in OS10.1.2 but less impressed by the fact that in OS9.1 iTunes 2.0.3 refused to recognise the CD writer even after installing authoring support and disabling the USB and Firewire Authoring Support extensions. Odd, because the LaCie drive is listed as being supported on the apple/itunes website.
It transpires that LaCie have changed the drive inside this unit and the new one isn't yet compatible with iTunes.
But there is a workaround for many external CD writers that iTunes won't recognise - iTunesHelper is a freeware app that you can get from
http://www.ituneshelper.com - it simply fools iTunes into thinking you have a brand of drive it *does* recognize. And it worked for me - just told it I had a Teac not a LaCie and I'm burning merrily from iTunes! (in OS9.1)