Radioactive Press have made their Mega Bots rules available from RPGNow.
From their announcement:
Mega Bots is a turn based combat game for two or more players set in a world where conventional weapons of war have been replaced with gargantuan robots. The game allows players to create and control a robot armed with a variety of weapons and special combat systems. Mega Bots gives players complete control over the creation of their bot. Players can create an existing bot from popular media or one from their own imagination. The possibilities are endless. The object of the game is simply to turn the opposing bots into scrap metal.
Mega Bots is a standalone game that can also be used as an expansion for any other Toy Battle System game. Other Toy Battle System games include Giant Monster Rampage 3rd edition and Power Warriors.