If the music is in mp3 format you will be able to import it into iTunes. The video will most likely have to be converted in to an iTunes friendly format. There are several utilities available to do the conversion for you. Unfortunately, I have not used any since I don't own a video iPod. A google search should provide you with several options.
I recommend that you download iTunes from Apple's site. It's free. That way you can become familiar with it before the iPhone is released. Anything you are able to put into iTunes should be able to be transferred to the iPhone.