Tom Riggs
I am not a master mixer by any means but the way I approach it is I make sure the bass and the kick have some content at higher frequencies. In the case of the kick I try to pick a kick and eq it so I can hear the smack of the beater against the head not just the boomy part. That way if the playback system lacks low end the kick is still there.  I take a similar approach to the bass so that the overtones of the fundamental help out when the bottom is lacking. Just make sure there is room in the mids for the vocals and other instruments. Usually sweeping an eq with the kick or the bass soloed helps to find the upper frequencies that can be helpful. I also check my mixes on several phones and ear buds as well as the studio monitors and stereo and regular pc speakers.   

Maxxbass is great for this sort of thing.

There are not different mixes for CD's and iPods. There the same mix. CD's are generically ripped into a PC and installed into iTunes or another app. Then its transferred to an iPod or another ear-bud player.
There the same mixes, they just got converted to a horrible MP3 bitrate in most cases.
 
Its very possible to mix a song that plays well om ear-buds and huge stereo speakers. Its done all the time and probably being done right now in a studio near you :)
 
CJ

I seem to have been misunderstand by people who think I don't know a fader from a piano key.  I know that one mix can sound good on on different systems.  But just like people made small adjustments to mixes so that--while still sounding good in the studio--they worked well on mono TVs and AM radios, I was discussing what minor tweaks might be made so that a mix that sounds good in the studio does not sound overly ugly when subjected to the bizarre EQ of common earbuds.
 
Several people have told me that if a mix is good it works everywhere.  Fine.  I will just look up the definition of good mix somewhere and we won't need to discuss it anymore.

Konrad I belong in the one mix fits all camp. The problem I see with trying to mix to a crappy system is which crappy system to use? All ear buds are not the same so how do you decide which to test and mix for? Ah, you would use the most popular, right? and can you be sure of that? At which given time would that apply? Now in the end you will have a half dozen mixes most of which will sound awful on a good system and the others, well no one will care. But you will have a very bad reputation for producing bad sounding mixes. Of course you could label everything with what it should be played on. "This should be played on crappy systems".  That should go over well.
 
I look at it that what some one chooses to use as their listening device is their problem and should not concern the mixer. His duty is to make the best sounding mix on the best system he can. Those that choose crap will hear crap and those that choose quality will hear quality. To me that is the way it should be.
 
 

I think many are over-complicating it.  Cjay nailed it very simply the first time.  If the song is properly mixed and mastered it will sound just find on earbuds.  Yes, one could go through the trouble of tweaking it so it sounds even better on earbuds, but why bother going throuhg that much trouble to be that precise for a medium that is not that precise to begin with.  The average music buyer is listening to mp3s ripped from standard masters and nobody is complaining that they wish songs were mastered specifically to their $1 store earbuds.  Doresn't hurt to take a listen to a song in earbuds, but I would not make a single change to accommodate for them.  My son made the mistake of mixing with and for earbuds and got the shock of his life when he played his songs on quality speakers.  It was a boomy, muddy mess.

I will just look up the definition of good mix somewhere and we won't need to discuss it anymore.

Well said.
 
I'm in the do-it-once camp, too, but if I somehow had a requirement to mix specifically for stock iPod earbuds (maybe Apple wants to preinstall my song in the samples folder) I'd give it a low shelf boost around 80Hz and a gentle broad dip around 4KHz. There's no point trying to boost the low bass.

Thanks, bitflipper.
 
I seem to be having trouble getting through a bit to some folks: 1-Yes, one mix 2-Auratones. [:0}