Is there such an effect in photoshop I cant's seem to find it. Or is it under an other name?

Are you talking Perspective? That is found in Edit - Transform - Perspective. Also, there is a Plug-in called Andromeda Perspective Filter v1.1 which can be downloaded.

Not quite sure what effect you want to achieve, a common method of faking gradual loss of focus with distance is to make a copy of the layer you want to give the illusion of depth to, Gaussian Blur it to the maximum soft focus you want, apply a layer mask to the blurred layer and draw a black/white gradient into the mask to reveal only as much of the blurred layer as you need. Hope that made sense.

If you are trying to make this on a picture made in a 3D Program, you could see if your program supports saving the z-buffer. z-buffer has the depth information of the image and can be used as a mask when using gaussian blur as advised by lundqvist on the previous reply. If you are editing a photograph you have to make the mask by hand as photos don't have depth information.

Bryce has a distance mask render option as well. It makes a perfect alpha channel for Photoshop where you can gaussian blur the foreground and background. You can increase/decrease the contrast in this new alpha layer to simulate different focal lengths.

You can also select certain areas of the z-buffer/distance masks with Photoshop's "color range". This way you can modify the "camera's" place of focus. For example if you do color range with 50% black (grey) and then invert the selection you can blur only the foreground and the background. The middle area of the image is then maintained in focus.

Andromeda Vari Focus plugin