WordPress suddenly didn't allow me to upload swf's anymore. Discovered this plugin and put it to use. Only tried it just now - it's working perfectly. Of course I can't judge whether it has any issues.
One tip: if you try to set the file types, you have to go to Settings>Allowed Mimetypes. The rest is pretty self-explanatory.
Oh, and I'm using the very last WordPress version (3.7.1) though the plugin hasn't been updated for this version. Hope thst won't cause any trouble.