3GP format is easy to convert, simple and light resource

Did you know about File Extension 3gp?
File Extension 3gp is multimedia files that are often used as a complement to the distribution of multimedia throughout the 3G mobile phone network. Why this type is often used around the world by almost every provider of mobile communication? because the file structure that can reduce bandwidth usage and can save the storage media, File Extension 3gp format derived from the MPEG-4 format

Can I convert to another format and what kind tools used?
Yes you can convert File Extension 3gp to another format, Free 3GP Video Converter its one of them. It Convert 3GP to AVI, 3GP to MP4, 3GP to MP3 audio and back AVI, MP4 and others to 3GP.Convert 3GP video files recorded with your cell phone to more common PC video formats AVI or MP4 or back other video files to 3GP. Extract audio from 3GP video files. It's clearly free and absolutely safe to install and run.its free for download you can visit http://www.dvdvideosoft.com/products/dvd/Free-3GP-Video-Converter.htm get the latest version 3.1.3.51

How do I play?
VLC Media Player and MPlayer are two open source programs with the support of 3 gp. Both programs have versions for Linux, Mac, and Windows. File Extension 3gp vulnerable to damage and corruption that occurs when transferring files from phone to computer. If the transfer is interrupted, the possibility of data can be lost or damaged during the data transfer.So you must be carefully handling when data transfering data to PC.