iPhone can play MP4 and H.264 video, when you finished download limewire videos, you have to convert them to the right format, Aimersoft iPhone Video Converter can help you do that, just follow these steps:

1. Download and install Aimersoft iPhone Video Converter, you can Download the latest version from here: http://www.dvd-iphone.com/aimersoft-iphone-video-converter.html



2. Run Aimersoft iPhone Video Converter, click “Add” button to import your downloaded limewire video, then click “Start” to start the conversion, the default setting works perfect.
3. Open iTunes, find your converted video on your hard drive, and drag the video to your iTunes library, or click iTunes “File -> Add File to Library” and import your video to iTunes. Connect your iPhone to computer via USB cable, when your iPhone is detected by iTunes, iTunes will sync the video to iPhone automatically, done.

If you want to transfer free youtube video or stream vdeo to iPod, PSP, Zune and iPhone, you can refer to this guide:
http://www.aimersoft.com/tutorial/free-download-youtube-video.html