On the 20th of December 2010, Minecraft will go out of alpha and go into beta.

This is what the creator, Notch, had to say

"When the game enters beta, the price will rise *from 9.95 Euro* to 14.95 Euro. (Was $13.33 AUS, now $20.05 AUS)

We will also change the license to remove the line that promises all future versions of the game for free. Please note that this change only affects people who buy the game after December 20, so if you got the game for during alpha, you will still get all future updates for free, despite this change. A promise is a promise.
Buying the game during beta will include all updates up until release, of course, and bug patches will be free."

What does this mean?

When future updates of the game comes out, they won't be free any more. Expansions and updates will cost you money.

However, people who bought the game during alpha, it promised all future updates to be free.

SO, You have SEVEN days to buy an ALPHA version of Minecraft to get free updates forever!

Aaaaaalready got it

I probably should have posted my thanks for this information Emilia, myself, lifesapity and DeMoN all got Alpha accounts as a result