Latex provides commands for all sorts of arrows. The following commands are used only in math mode.
In general the command names are created from "left", "right", "up", or "down". "leftright" gives a double headed arrow. Prefacing with "long" gives a longer arrow. Capitalizing the first letter gives a double-shanked arrow.
Examples are:
\leftarrow
\Leftarrow
\longleftarrow
\Longleftarrow
\rightarrow
\Rightarrow
\longrightarrow
\Longrightarrow
\leftrightarrow
\Leftrightarrow
\longleftrightarrow
\uparrow
\downarrow
\Uparrow
\nearrow
points from southwest to northeast
\searrow
points from northwest to southeast
\swarrow
points from northeast to southwest
\nwarrow
points from southeast to northwest
The
\stackrel
command is
useful for putting things over or under your arrow.