Here are some free video players that can play FLV files (most of these are for Windows) :

  • VLC media player is my personal favorite. Aside from FLV it also supports a wide range of video formats and is one of the most reliable players I’ve ever used. Doesn’t require any external codecs.
  • FLV Player, an aptly named and simple to use freeware app.
  • Moveya FLV player – not bad, can make screenshots and play online videos.
  • Wimpy FLV player – the main selling point of this freeware player is that it supports both Windows and Mac.
  • nFLVPlayer (requires the Flash Player). Can play videos directly from the web.

On a related note, check out this tutorial to find out how to add FLV support to Windows Media Player.