3GP is standard media format for video files and MMS handled by GSM and CDMA phones: Nokia, Samsung, BlackBerry. Unlike MP4, 3GP video files require less storage.
Freemake software lets you download and convert favorite YouTube videos to 3GP fast. Convert YouTube music & online movies to 3GP or 3GP HD. Use ready conversion presets and export small 3GP media files to your smartphone instead of huge MP4.
Here's How to Convert YouTube to 3GP in 3 Steps: