Do you want to download a video from a video sharing site like YouTube and play on your mobile phone? You just need an online service like Zamzar. Just provide the URL of the video. Select the format in which you wish to receive the converted video. Here you want it to play into your mobile phone, so .3gp format would be most appropriate. Provide your email address where the converted file would be mailed. In few days, your desired video will come through email. Download it and transfer it to your mobile phone. That is it. You can utilize this service for free provided you restrict file to be converted up to 100MB. Not just videos, you can also utilize this service for converting other file formats as well. Say from PDF to Word File.