Free Video to Flash Converter has this very specific purpose: converting video files to Flash SWF or FLV video formats. It supports the most popular formats (AVI, MPEG, WMV, MOV, etc) and works really fast.
The program's interface is pretty straightforward. Simply select the source video, the target format and location and you're done. What's more, if you select SWF the program will also generate all the necessary HTML code and documents.
Another feature we liked was the embedded trimming tool: if you don't want to convert the whole video you can use it to select the fragment you're interested in.
As with other DVDVideoSoft apps, Free Video to Flash Converter includes significant enticement to download other tools by the same developer.