One thing to watch out for people learning IA-32(e) asm is that there are two syntaxes: Intel and AT&T. Intel, unsurprisingly, uses Intel syntax. GCC, however, mostly uses AT&T syntax (for historical reasons, and that's all I'll say).
You can find a reference to the GAS syntax at http://en.wikibooks.org/wiki/X86_Assembly/GAS_Syntax. I wouldn't use it for a reference to any of the instructions (for that grab the linked Intel manuals in this article), but that should get you familiar with the differences if you decide you'd like to write GAS.
You do have the option to set GAS to use Intel syntax with a directive, but if you're modifying legacy code or just want to be consistent with a lot of other GAS code, you may want to use AT&T.
One thing to watch out for people learning IA-32(e) asm is that there are two syntaxes: Intel and AT&T. Intel, unsurprisingly, uses Intel syntax. GCC, however, mostly uses AT&T syntax (for historical reasons, and that's all I'll say).
You can find a reference to the GAS syntax at http://en.wikibooks.org/wiki/X86_Assembly/GAS_Syntax. I wouldn't use it for a reference to any of the instructions (for that grab the linked Intel manuals in this article), but that should get you familiar with the differences if you decide you'd like to write GAS.
You do have the option to set GAS to use Intel syntax with a directive, but if you're modifying legacy code or just want to be consistent with a lot of other GAS code, you may want to use AT&T.