As long as you are still running 2.3 you can move them to sd using the applications menu: select the app, click on it, and if you can move it there will be a "move to phone" button amongst the options. If the button is greyed-out then the app can't be moved.
If you are running android 4 or later this option no longer exists.
Remember that only part of the app is moved - your internal space will still decrease as you add apps (and app data remain in internal regardless).