If you are serious about making Flash movies/games, get Flash. Nothing compares to Adobe Flash when it comes to making flash animations. Liveswif, and whatever other imitators are out there can make flash but they are not nearly as great as Flash is (I've used liveswif, and swishmax, they really don't compare to Adobe Flash)
If however you just want to make games, go get yourself FlashDevelop (the IDE) and Flex 3 SDK (the compiler). They're both free. On the 'downside' (if you're new to flash) this is code only (and AS3).