Did a client just deliver some FLVs but you have no way of viewing them? It happens.
In fact, it just recently happened to a buddy a mine. He sent me an email essentially asking "How can I view an FLV file?" The quick answer is: you need to create a Flash file that uses the FLVPlayback component and that component should point to the FLV that you want to load.
After a quick googling, I found several articles that explained ways to build a viewer and a few open source options that required a download. But, I was unable to find a simple solution where you could just point to the FLV (on a web server) and view it. The solution: build one.
The result: I whipped up a very simple FLV Viewer that allows you to paste a URL to a FLV file, click "Load and Play," and watch.
So go ahead and check out the simple FLV Viewer. Hopefully this helps someone out!
Quick note, if you're having issues running FLVs from your server, be sure that you've set the MIME type on the server accordingly. You can read about configuring your server for FLVs from Adobe.