It's quite easy. This is a very good help. You don't need to be using GNUpod to flash your iPod in Linux. Although it does assume that you have a Windows-formatted one. If you have a Mac formatted one and your system doesn't understand Mac partitions, use parted to delete the partitions, then go into fdisk and basically go:
n (new partition)
p (primary)
1 (1st partition)
(enter)
+32M (32MB in size)
n
p
2
(enter)
(enter)
t (set type)
1 (1st partition)
0 (Empty)
t
2
b (W95 FAT32)
w (write changes)
sync
mkfs.vfat -F 32 -n "Volume Label" /dev/sda2
eject /dev/sda

^ that should initialize your iPod, if it's freshly bought. but yeah. updating the iPod is a lot easier than I thought. I think I might make a rudimentary GUI for it ^_^

You're such a brown-nose, Keith. Anyway excellent job on the tutorial.

We need more documentation though. You need to get right on that, on the off chance I get an iPod. :p