Restore SMS icon in default home lancher?
On ICS, click on the applications icon, then select menu &gt; edit. You can now drag-and-drop any application icon you want to the row with the default icons.

Note that you can remove the phone and contacts icons, but not the applications icon.

I'm not sure if there is a similar feature in the TouchWiz launcher on Froyo, but alternatively you can look around and install a different launcher that does allows you to customize everything. You may want to start by reading this article