I'm assuming you want to learn x86 assembly. In school, we learned how to program in MIPS.
If you're wanting to actually program in it, learn the concepts of assembly, and use an x86 reference guide. If you're just wanting to reverse, get all 40 of lena151's tutorials. Though, I'd suggest actually learning it and becoming fluent in it instead of just learning it for reversing, until you can basically translate it into a higher-level language.