Upgrading from:

Graphics`Arrow`

Arrow has been added to the built-in Mathematica kernel.
New directive Arrowheads has been added to the built-in Mathematica kernel.

The built-in Arrow takes a list of points instead of just start and end points:

Version 5.2 << Graphics`Arrow` Show[Graphics[{Arrow[{0, 0}, {1, 1}]}]]

The Arrowheads directive controls the size, position and appearance of the arrowhead:

Version 5.2 Show[Graphics[{Arrow[{0, 0}, {1, 1}, HeadLength -> 0.1, HeadCenter -> 0.4]}]]