You need two things: a flv encoder and a web-based flv player.
Why? Because a flv encoder is used to convert your avi to flv and a web-based flv player is used to play the resulting flv on website.
First thing, flv encoder. Good and free flv encoder like Moyea Video4Web Converter, which you can try. The second thing, flv player. You can use playerdiy.com, it is a quick way to make flash video player for website.
On mac, Doremisoft AVI to Flash converter for mac makes these tough work easy by a few steps. With mac AVI to FLV converter, you are allowed to convert the common format AVI to FLV(flash video), convert AVI to SWF and generate a HTML web page embedded with Flash video.
You can convert Shockwave Flash (*.swf) files into Screen Saver files (*.scr) using a program like InstantStorm, see the related link for their homepage.With a FlV converter, convert FLV or .swf files to gif or aiv.http://www.sharewareguide.net/article/Tip/avi-to-flv-converter:-how-to-convert-avi-to-flv-file.html
I think the FLV to AVI MPEG WMV 3GP MP4 iPod Converter is your best choice, it always works well for me. it can convert Flash Video FLV to AVI, FLV to MPEG, FLV to WMV, FLV to MP4 format.with excellent quality.
The best way to convert FLV to AVI is to use software program
You can use SWF & FLV Toolbox by Eltima Software.
Use a video converter software to convert flv files to mpg files .
Windows media player doesn't support flv format,so you can't play the flv files on it. You can use convert flv files to wmv,avi,mp4,etc. I recommend you 4Media FlV to WMV Converter.It is the professional FLV to WMV converter software which can convert FLV videos to Windows media files including WMV, ASF videos and WMA, WAV, MP3 audios for playing on Windows media players and Windows mobile devices.It's easy to use.You can have a try. You can use VLC player
uSeesoft FLV Converter can do it for you it can convert FLV and YouTube videos to almost any video/audio format with unmatchable conversion speed and high quality, such as converting FLV to WMV, converting FLV to AVI, converting FLV to MP3, converting FLV to MPEG, converting FLV to MP4, etc.
I use a Flash to Video Encoder PRO. Very easy to use program. You can convert flash files to video movie AVI, mp4, ASF/WMV, mpeg files, etc.
You can watch FLV with Moyea FLV Player. you can download FLV with Moyea YouTube FLV Downloader. You can convert videos to FLV with Flash Video MX Pro. You can convert FLV to Videos with FLV Editor Pro.
Google "FLV Converter for Mac" and find (buy) some software that you install; follow the manual.
Most understandable tool for this conversion is the SWF & FLV Toolbox, which can convert SWF and FLV files to AVI video format with high quality and mp3 sound. Then you can write the output file on CD or DVD and watch it on any video player.http://www.swf-kit.com/convert-swf-to-avi.html
You would most likely want to use Mencoder and a graphical front-end. If you use KDE, try KMencoder. If you use GNOME, try GMencoder.