You can use Flash Video Encoder to convert most video file types into an FLV file, which is basically a Flash video file.
With Flash 8 you can now choose from two codecs, the original Sorensen Spark video codec, which is compatible with Flash 6, 7 & 8, or the much newer and more advanced flash video codec, the On2 VP6 codec.
Basicially put - if you want backwards compatibility back to Flash 6 players, use Sorenson, and if you want the latest greatest compression etc, and you’re designing for Flash 8 Players, use the On2 VP6 codec.
Since Eolas ruling has broken Internet Explorer’s embedding of Flash content using OBJECT or EMBED tags, SWFobject is another solution (which is in fact a great improvement over the older methods of embedding SWF files).
I strongly recommend anyone working with Flash trys SWFobject (formally known as FlashObject).
