By beta, I think you mean "snapshot" and they can be found on Mojang's website: mojang.com
The beta version of Minecraft was released on December 20, 2010.* * Minecraft-beta came after Minecraft-alpha, but before Minecraft 1.0. You can play Minecraft-beta with the new launcher.
piston are all ready on the new minecraft beta and they will mot be removed.
no you need minecraft beta to play beta servers
The regular download as of Minecraft 1.8 is the Beta Minecraft. The last Minecraft update I believe will be the "Final" product and official game and no longer be a game in Beta.
When the full Minecraft game is released you will have it if you buy the beta.
Minecraft isn't in beta any more, but they are still bringing out updates so far. Mojang havn't given a date for the new update. (as of yet)
Minecraft is currently scheduled to leave beta November 18th of 2011
No. It was a new feature released in Beta 1.4.
Beta 1.0
Yes. And Minecraft Beta 1.8 with crafting, furnaces, chests and stuff is called "Minecraft Beta" or "Survival Mode".
Alpha was an earlier version on minecraft beta, it has poorer graphics, less blocks and far fewer crafting recipes.
No