Maya has an Aim Constraint that easily accessible and completely capable. However, there are times when the native aim constraint can get a little confused depending on how it is incorporated and used.
Here, Jeremy Parrish shows how you can essentially make your own Aim Constraint setup in Maya using a couple of nodes and connections. This set up will get you primary behavior of the native Maya Aim Constraint, although will not give you some of its extended functionality – instead focusing only on the relative angle of an object.