Add Mp3 to Iphone

Have iphone connected to dock
Double clik on itunes icon
(Itunes should appear)
scroll on the left search bar that shows your playlists, library, store and devices
under devices click on iPhone
it will automatically be on the summary tab
click to the music tab
click sync music box if not already checked and click on All songs and playlists or selected playlists
(i suggest selected playlist because if you have a bigger library of music you can select what you want and dont want)
then click on all the playlists you want on your iPhone
after you are done click apply then sync
violla (done)
IF YOU HAVENT BUILT YOUR iTUNES LIBRARY SEE BELOW

it would be easiest if you put all your music in one file
once that is done click file > add folder to library
here you will b able to find the folder you put your music in
it will load the music into itunes and you can begin making playlists (or make smart playlists)

http://www.iphone-hacks.com/forums/post-707.html