From Dampfpanzerwagon.
I've also attached a link to my Blog, but Westfalia Chris has already commented on my collection of 40mm Flash Gordon miniatures (my ever growing collection).
I use Fantastic Worlds, there is a free download (or there was) of sample rules if you want to 'try before you buy'.
I also have;
To Be Continued By Gaslight by John R. Buck and Christopher Palmer.
Space Rat by Nathan Russell.
Some notes on Flash Gordon for Savage Mongo Adventures that was released with Monolith Design cards.
Void Trek 3007A.D.
Legends in Time and Space, Dark City Games.
Rockets and Rayguns, by Angelfire.com
Plus others! I am a bit of a Flash Nut!
I hope this helps.
Tony
http://dampfpanzerwagon.blogspot.com/