Syncing iPod 60GB & iPhone 8GB to 1 iTunes/1 Computer

Hey all, thanks in advance for your help with my question. I am wondering how to sync my iPhone & iPod to the same iTunes/computer(iMac G5 1.8) while being able to separate what goes on each of them in terms of music, etc
automatically in the process. For example, my iPod is a 60GB so all my music will easily fit onto it, however, the iPhone is only 8GB so limited in what will fit. Needless to say, how can I manage them individually on the same iTunes?
Hopefully my explanation will get across what I'm looking to find. Thanks again and have a good week.
CBB

Well what I do is... I sync almost all my music to my iPod using sync all music to iPod but unchecking things I don't really want on there. For the iPhone I sync using playlist and selecting custom syncing. Bands that I really like I usually combine albums into one playlist. Artists that I only one album I just drag the album art to playlist and it's there. Then in iTunes you go to the music tab with iPhone connected and click sync selected playlists and put a check mark next to what you want on there.