Lots of different options on gapless and coding formats. And it does depend on both format of file and player. If you're looking for REALLY SIMPLE from the IPOD point of view, you could rip your CDs with ITUNES into AAC format at maybe 192 or so. You'll find that this is transparent for many, many listeners, and this automatically works as gapless on both ITUNES and the IPOD. Even MP3 files ripped from almost anywhere (including ITUNES) are mostly gapless. LAME encoded MP3 files are gapless in many different players, including IPOD.
I personally use LAME encoded MP3 files (-V2 new) to play on my IPOD. I have many live concerts and gapless albums and all work perfectly gapless on the IPOD (and on ITUNES). If you really want to know more about this, search on "gapless and ipod" or "gapless and itunes" and you'll find enough reading material to keep you busy for a few days. EDIT: to get you started:
http://www.hydrogenaudio.org/forums/index....c=48231&hl=