I am using Fedora 15 with Gnome 3. The window title bars have only a Close button as control button. If you want to add other buttons here is what you need to do.

1. Install Configuration Editor

You can skip to step 2 if you have Configuration Editor installed.
Press Super (Windows) key and type Add/Remove and open Add/Remove Software.
Search for gconf-editor and install it. You may need to wait a while if you are using Add/Remove Software for the first time.

2. Use Configuration Editor to change button layout

Launch Configuration Editor.
In the Configuration Editor navigate to desktop>gnome>shell>windows
Find button_layout and enter the following to add Minimize and Maximize buttons:

:minimize,maximize,close

If you want Ubuntu-like control box, enter the following instead:

close,minimize,maximize:

3. Log out and log back in

The changes are not instant. You either need to restart Gnome shell using Alt+F2 > r > ENTER (as reader Elliot pointed out in the comments) or you need to log out and log back in to see the changes.

Hope this helps.