Springboard Modification
I have read about two ways to do this. 1st is to get a transparent png file, SSH into phone, and put it into theme.xxx folder under bundles\com.springboard.app and rename them as following:
WallpaperIconDockShadow~iphone.png
WallpaperIconShadow~iphone.png
You will then have to go into winterboard and select theme.
If you are not using winterboard, you can always go SSH into phone, go to System/Library/CoreServices/Springboard.app and rename the files above to .bak instead of .png
I have found it much easier to do the second option. Make sure to respring to complete changes.