How can i convert .avi to 3gp videos with same quality of audio and video?

I would like to share you a best converter i have used:
I recommend you a useful and free tool that can convert video, rip dvd, Backup DVD and download YouTube video.
you can download this tool at here:
http://www.google.com/search?hl=en&q=htt...
it called "Next Video Converter". It is easy to use, you only need click few button.
Next Video Converter is a free video converter and DVD ripper with easy-to-use graphical interface, fast converting speed, and excellent video quality. It can convert almost all video formats including DivX, XviD, MOV, RM, RMVB, MPEG, VOB, DVD, WMV, and AVI to MPEG-4 movie format for iPod, iPhone, PSP or other portable video device, MP4 player, or Smartphones. It can also rip DVD to any video format.
4Easysoft Total Video Converter:
Click here to see the full reviews and have a free trial:
http://www.4easysoft.com/total-video-con...

Free Download, Flv to 3gp Software Collection Download.

This article shows you how to Extract audio from Flash video, FLV to MP3(MPEG Layer-3).

Software for 3gp 3g2 video converting, convert any video to 3gp 3g2.

It can convert almost any the video format to another with high output quality.
This full-featured video converter software also can help you:
1.convert between all mainstream video and audio formats,such as(mp4, 3gp,mov, m4v, vob, XviD, avi, flv, 3g2, mpg,wmv,etc;m4v, mp3, wav, ac3,etc)
2.extract audio tracks from video files to other audio formats
3.support all popular portable multimedia players
4.edit video-Merge, Trim, Crop and Snapshot
Just try now.Hope this can help you