Rockbox started as a reverse engineered alternative firmware for certain Archos MP3 player/recorders — now Rockbox varieties support machines from Archos, iRiver, iAudio, and Apple. What Rockbox provides for iPod users is an alternative operating system for several models of iPod. It works with the two most recent generations of (full-sized) iPod, as well as with the nano and Mini varieties.
Rockbox uses, by necessity, the iPod's click-wheel input system and employs a similar nested-menu navigation. Casual iPod users might not feel instantly at home, but will probably be comfortable enough with the menus after a few minutes futzing around to start playing music. However, once a user starts exploring those menus, he's likely to spend quite a while exploring the long lists of fonts, games, and options they offer. Among those options are several things which as far as I know are still missing from Apple's firmware, including cross-fading of tracks (so songs blend into each other, DJ-style) and gapless playback.
Unlike the original user interface (UI), Rockbox uses [a] simpler, nested-folder system to manage music as well as other types of data, so you can drag and drop music straight to the window representing the drive's contents. Rockbox will not read the obfuscated format used by the original iPod software. For good or ill, that means no longer relying on an application like iTunes or gtkPod to manage your music.
This Definitely Sounds cool, I will be trying Rockbox on my ipod. For Those of you who dont know, I own an Ipod Mini 6 GB 😛