The smartphone / tablet and operating systems don’t make it easy to centrally administrate them these days.
A few weeks ago, we ordered 6 Samsung Galaxy Tabs 7.0 and 10.1N, current with Android 3.2, and had to find a way for this.
The additional software Good for Enterprise may be a good tool, but is too expensive for us.
At least there is a free way to block app installation and changing the settings of the tablet, e.g. with Smart App Protector Free. You can choose the apps which you want to lock, e.g. with a password.
Hopefully, the upcoming Windows 8 devices will offer more group policies (Active Directory etc.).