Logic operators in LaTeX? (XOR?)

\oplus worked for me :)

I found this in List of logic symbols :P

How about \newcommand*\xor{\oplus}?

What you're looking for is \veebar in amssymb.

\usepackage{amssymb}

$\veebar$

If you like, you can create a new command \lxor, named to match \lor and \land:

\providecommand{\lxor}{\veebar}