In most Android devices the path is: menu > settings > applications > manage applications > menu > sort by size..
..then wait until it's all sorted (as a matter of fact, prior to hitting "menu > sort by size" it's best to wait until the app list has completely loaded)..
..next go to each app individually and click on it, then you'll see the appropriate buttons. You'll have to do that with each app.
Then power down your device, wait a minute or so, and turn it back on.