how do you get rid of shadows in a picture with photoshop cs4

The link below may get you some ideas.

http://www.photoshopgurus.com/forum/quick-tips-techniques/22635-how-get-rid-shadows-portrait.html

If you need to lighten the whole photo, you can duplicate it and set the top layer to "screen".  Adjust the opacity and it'll lighten the whole image.

Or, to fix a shadow (a mild one, this won't work for really bad shadows), you can do the following:

- Create a new layer above the photo.

- Choose the brush tool.

- Choose one of the circle brushes (the kind with a soft edge, called "soft mechanial")

-  Paint on the new layer.  Cover the area where the shadow is. (don't do anything directly on the photo layer itself)

-  Set the layer to "soft light".  (You can find that in the blending mode drop down menu, which is found on the layers palette at the top.  "Normal" is the default, but if you click on it, you'll see the drop down menu.)

- Adjust the opacity so it'll blend nicely.

It's a quick and easy way to fix dark spots. 

here u go: tutorial

Apply Eye Make-up

How to remove shadows from photos in Adobe Photoshop

hope it works.