Has anyone noticed that you can charge your iPod via FireWire when your Mac is sleeping? Put your Mac to sleep and then plug your iPod in. It will charge without being mounted, until either you remove it (just pull the cable out), or you wake your sleeping Mac (when it will be mounted. This works on my iBookG4 (2005).
[robg adds: Yes, this is a somewhat obvious hint, especially for long-time iPod users. However, it gives me a chance to mention a related issue with USB-based iPods: USB-based iPods can not charge via USB while the machine is sleeping. My wife's PowerBook isn't used during the day when she's at work, so it sleeps. Having no experience with USB-based iPods, I plugged her Nano in, assuming it would charge while sitting there. I was quite surprised to find it basically drained a few days later (she used it some in the interim).
Some simple experiments showed that the USB port won't charge a USB-based iPod if the Mac is sleeping. This is true even if you route the iPod through a powered USB hub. So instead, we bought a FireWire wall-plug unit and a FireWire-to-Dock-connector cable. Now she has to manage two different cables, one for charge only and one for sync, but it works.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20060301125140795