How to the music from PC to an iPhone 4?

How can i get the music that is save on my PC computer on to my iPhone?

I know how to getting it off iTunes.

With bluetooth?
Do you have bluetooth on your pc?

You can either add the songs to your itunes library and sync the iphone with that computer. If you wish to add them manually, download a program called iFunBox. It's completely free and allows you to directly interact with the filesystem of your phone.