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.

x86 assembly has probably the most complicated instruction sets of any CPU, its almost impossible to learn just by doing a tutorial

I recommend starting out with MIPS instead, there are a lot of good tutorials and books for MIPS assembly

if you really want to see what x86 assembly is like then there is an assembly training video at www.vtc.com which will give a brief intro