I don't know if this will work for everyone, but here is how I convert .flv's into .mpg's.
1. Download the latest free version of realplayer at
www.real.com and during the installation process, check the box that says something like do you want to enable realplayer to save clips.
2. Go to a website that has an .flv clip that you want to keep and start playing the clip.
3. When the clip starts, there will be a small pop-up tab that appears in the upper right hand corner of the clip asking if you want realplayer to download the clip.
4. Download the clip to completion.
5. Open realplayer and view library. The clip will be there.
6. Right click on the clip > click on move file to... and move it to a folder of your choice and close realplayer.
7. Open that folder and click on organize.
8. Click folder and search options.
9. Click view.
10. Unmark hide extensions of known file types and exit. Now when you are in a folder, you will see the clip name ending in .flv.
11. Rename the clip by deleting the .flv extension and replacing it with .mpg. You can also call it .wmv or .avi etc...
12. Voila, you now have an .mpg that should play in any mediaplayer.