I just bought beta, when so I get my key or whatever and how will I download the game?

Title says it all guys.

youll get your key when it switches to beta (anytime in this next month hopefully) and when the game goes beta it should appear in the keys area of you uber account, though dont quote me on that last one

If you bought it through steam, you can download it through steam. Otherwise, you download it with the standalone launcher.
Beta comes out this september. When exactly in september is anyone's guess.

i was 90% sure you could only buy the alpha version on steam, i may be wrong though

right, my bad.

alright guys. thanks for your help and reply. Deeply appreciated. I can't wait to start the game. any tips on how to get a knowledge on it, so I can find it easier when i start playing?

start watching videos and casts of them, for example zaphodx is great
http://www.youtube.com/user/ZaphodX1

You can also visit my website, lots of PA videos, news and mods! It's in my signature

Petardia.com. It's a bit slow, as Petard is running it off a budget server I think... But it contains literally all the information you will ever need for PA. I'd reccommend you watch one of the games either Godde or Cola Colin is in. There is one really good one where both of them go up against one another, I think it was casted by ZaphodX.