Myspace always hates my computer and never loads music (it could be user error), so my advice is sight-unseen (gasp!).
Here's a few tips that I take to heart when I mix (and of course, tweak to your own tastes as you see fit).
The most important range, IMHO, is around 3k-4k. This is where instruments "cut" through the mix, really. There's a word for this point for opera singers, but I can't remember what it's called - basically, every voice has a super strong point somewhere in this range, and it's different for every person. Anyway, guitars and vocals tend to fight in the mix over this frequency - best thing to do is cut this range (with a somewhat wide Q) on the guitars when vocals are in the mix, and boost it on the guitars when the vocals are out.
I believe that the absolute lowest thing in the mix should always be the kick drum, and I always give it a bit of a hump around 50hz.
Bass guitar I think of as keeping a good "thump" sound, so I let it dominate lower frequencies (but still above the kick) around 200-400. If you go overboard, though, this frequency range can make your bass sound muddy.
Once you mix it down to two tracks (in other words, am mastering your overall mix), it's nice to add a bit of high end to give your mix "sparkle." Just don't overdo it - otherwise everything sounds like breaking glass.