Do you have the needs of converting FLV files downloaded from video sharing websites like YouTube, Google Video, metacafe, Yahoo! Video, Reuters.com, etc. on your Mac? If so, I’ll strongly recommend you a pretty good FLV converter for Mac. The program I recommend is Pavtube FLV Converter for Mac, which can perfectly convert FLV videos to a wide range of video formats, so that you can do whatever you like with the resulted videos, such as playing on your iPod, iPhone, BlackBerry, PS3, Apple TV, etc. or exporting to iMovie, Final Cut Pro and Final Cut Express to do further editing, or doing something else as you like. A step-by-step instruction is involved in the following part, please read on it freely.
An easy-to-use DVD to iPhone software which enables you to convert DVD to MP4, H.264, MP3, AAC, WAV and M4A which can be played freely and perfectly on your iPhone.
1. Download, install and run this program
A sky-blue interface will be shown to you as follow: 
2. Add FLV files, set output format and destination folder
Mod Converter for Mac also helps you to edit your Mod file and optimize it.
Input FLV files to it by clicking on “Add” button, and select a format as the output format in the drop-down list of “Format”, meanwhile, you can press “Browse” button to specify the destination folder or just use the path set by default. 
3. Set advanced settings
Click “Settings” button, the following interface will pop up. You can change the parameters like screen size, bit rate, frame rate, sample rate, etc. to optimize the output videos.
Mac Mod Converter is the easiest to use mod video converter on Mac OS.
4. Convert
After all the above settings are finished, you can click “Convert” button to start conversion. Once finished, you are able to find out the output files via clicking on “Open” button.
This software can definitely complete the conversion at a swift speed without the problem of audio-video out of sync. Therefore you need not worry about these issues. Moreover, if you want to add watermark as your own logo or reserve your copyright, you can totally do it via making use of its “Editor” function.
More related info you may need:
Free FLV downloaders for Mac:
Web Video Downloader for Firefox
Free Video Downloader for Mac
Free YouTube Downloader for Mac
Free FLV player, Mac OS X:
Adobe Media Player
Wimpy FLV Player
QuickTime, after installation of the Perian video plugin
SWF & FLV Player