How to decompile / decode a .dll file

Hi !
Can someone tell me what do i need or how do i decode a .dll file.
Its Like this on start :
MZNUL ..........
how to make the real code show up.
Please help .You can't see it in the language it was written in but you can see it in assembly, which is very real. Use a disassembler.
Oh boy someone trying to leech
Well ida Hex Rays will decompile it into C syntax
o.O i know ima leecher. In fact im just learning C++ i was learning it before on the web. now i got a book. and i just asked this cause i got interested xD.