Assembler and tutorial

Can anyone link me to a good assembler and tutorial for Asm. I've tried Google but all I'm finding is broken links and DOS programs.
I'm using a 64 bit processor and am already familiar with programming in general.

>>67
It is when your “metaposts” are ``go back to /foo/'', ``I remember when /anus/ was good'' and similar sentiments.

^{>>65 was my first post in this vein of this thread. Please don't assume that I am any worse than you, I'm just trying to make more sense than the lesser-abled on their behalf.}