why is not android development available on 64bit?

i wanna create android application!
but i can not create development environment of the application.
because my pc is 64bit.

from now, 64bit pc might be growth....why is not 64bit available?

someone tell me about the difference between 32bit and 64bit...
i wanna know that.

now i try vareious way for creating the development environment.
come on!!!!
Go ahead!!!!