[Gemok]

If I understand correctly this is where the edges of the photo are darker than the center. Some photos I've scannned from the 35mm negatives have got this , is there an easy way to correct it in photoshop?
The prints the were developed along with the negs didn't show the effect is there a setting I should be looking to adjust on the scanner (canon 5000f)?

[Bachs]

New to Photoshop CS2 is a vignetting correction tool in the lens correction section.

Other than that, not sure.

[SammyC]

Well you could apply a brightening filter layer and use a mask that has a circular graduated fill applied from the center.

Not as easy as the custom tool in CS2 but will have the same effect.