Need a little help with a project. Electrical.

[teh DIRT]

So in my quest to find cheap replacements for overpriced electronics, Ive come up with another idea. What I need right now is what I think is called a linear actuator. I need a small light duty actuator no bigger than an ipod or a cell phone.(preferably)

This actuator also needs to be able to move to a position and stop there, then move to another position and stop there. Im pretty sure I can work that out with resistors and a combination switch though. So basically a small actuator that when given X volts goes Y distance and when X(2), y(2) and so on. Anyone have any leads?

[teh DIRT]

bump. anyone know where i can get something like this. I am starting to think of maybe using a R/C servo also, but I would prefer linear motion as opposed to rotational.