To transfer music and videos from computer to iPhone 3GS, you need to connect the iPhone to the computer using the USB cable that comes packed with the iPhone. Launch iTunes into your computer and wait for your iPhone to load in the menu. Click on the name of the music of video that you want to transfer to the iPhone and drag it to your iPhone. Check out http://www.ehow.com/how_5607520_transfer-music-pc-iphone.html.
Download iTunes on the computer , after fully installed, the go on www.mp3skull.com and download free music to the iTunes , then Connect your iPod to iTunes from the computer and sink all the songs in your iPod , iPhone or iPad