Latex: end of proof symbol

I was just looking after how to put the end of proof square myself in my Latex document. To put it on the same line as the last one of your proof and all the way aligned to the right (while the text is still left aligned), just type \hfill $\square$. To put it on the next line, type something like \begin{flushright} $\square$ \end{flushright}. I think you could use other commands to produce the square, like \qed or \qedsymbol, but I suspect you will have to use some AMS package.