First you need to encode your movie(s) in flv format with a Flash Video Encoder (Flix, Sorenson Squeeze, Adobe Flash Video Encoder,ffmpeg...).

You should encode your movies using On2 VP6 codec for best quality.

In order to reach the widest audience possible, you should encode all your movies with three different bitrates.
Basic choices are : 200kbps, 400kbps and 800kbps

For hi bandwidth, you should define the following parameters :
- Method : 2 pass, CBR or VBR
- Frame per second : the same as the source (for example 30fps).
- Keyframe : one keyframe every second (one keyframe every 30 frames).
- Size : Maintain aspect ratio and set width to 640 for better result in full screen mode.
- Audio : Stereo, 96kbps

For medium bandwidth, you should define the following parameters :
- Method : 2 pass, CBR or VBR
- Frame per second : the same as the source (for example 30fps).
- Keyframe : one keyframe every 2 seconds (one keyframe every 60 frames).
- Size : Maintain aspect ratio and set width to 320.
- Audio : Mono, 48kbps

For low bandwidth, you should define the following parameters :
- Method : 2 pass, CBR or VBR
- Frame per second : half of the original fps (for example 15fps).
- Keyframe : one keyframe every 2 seconds (one keyframe every 30 frames).
- Size : Maintain aspect ratio and set width to 320.
- Audio : Mono, 48kbps