I succeeded in mounting my Mac format iPod, but I needed a few extra tools since the n810 kernel doesn't read mac partitions (hint to nokia - turn this kernel option on).

1. You need to determine where the partition begins. I used od to print out the partition tables, but I'm planning on writing a utility. The details are in the kernel tree at /fs/partition/mac.*

2. Then you need to do losetup on /dev/sda to a loop device like /dev/loop0 (which the stock busybox won't do) with an offset to that partition.

3. You then need hfsplus.ko loaded,

4. Finally you can mount /dev/loop0 on /media/usb/sda1 or wherever, and access it. The auto detect feature of the file manager doesn't work, but you can put a symlink in a convenient location.

I was able to unzip a file from my video (5g) iPod.