ipodPJ, welcome to head-fi!
It seems your long posts have got some people worked up. This is because often new members post questions or suggestions that have already come up dozens of times in previous posts, and people go "jeez, not again! Didn't this guy do a search?"
Head-fi is actually a pretty friendly place, probably one of the friendliest forums on the net.
www.rockbox.org definitely exists, but the site appears to be down temporarily. They have suffered quite a bit of vandalism recently, and it could be they've shut down the site to repair the damage (as an open source project, anyone can contribute which includes malicious changes to the online documentation). I'd suggest you try again in a day or so.
Rockbox is software for iPod (and many other portable audio players), not Mac or PC, so it doesn't matter what computer you have, or what OS you are running (unless it's something really odd).
Custom audiophile line out cables are easily available for the iPod, and you can also take a look at the Amplification/Portable Audio forums because you'll need to buy a portable amp if you're using line out.
I'd agree that you could start with Apple Lossless on your iPod first, and then move to Rockbox if you really like the sound quality improvements.
IMHO Rockbox sounds better than standard iPod firmware, but this has been debated a lot and people have different opinions.
Also FLAC or WavPack are better supported than Apple Lossless in Rockbox, so if you go the Rockbox route, it may be advisable to convert your music to either format using Foobar 2000 which is powerful but can be a little complex, or dbPoweramp which is more straightforward.
The iPod can sound excellent, but personally I wouldn't use the onboard EQ, or reduce the volume of your music files. If you want more bass, use a portable amp with a decent bass boost, like a Xin Supermacro/Supermini or a Larocco PRII if you want to spend more.
I'd also agree with previous posts that iPods don't distort with EQ off, either using the standard iPod firmware or with Rockbox, unless the music file has been badly recorded, badly mastered or post-processed in some way.