Installing Non Android Market Apps
Most users use the simple to use Andoid Market to download and install new Apps on their smartphone/tablet, but users can install apps from other sources then the Andoid Market. Note, you the user is responsible for any applications you download and install, so always read the fine print, and it's very important to read the information on the app and what it has access to on the phone. If you don't agree to what the app makes use of (eg: GPS data is shared, ability to use the phone, access to SD card continents, etc).
Go to Menu, then 'Settings'.
Scroll down to 'Applications'
The First option is "Unknown Sources".. check mark this and you will be able to download and install apps from sources outside of the Android Marketplace.
Also, you can manage your applicatoins if you go back up one menu and select Manage Applications, it could take 30-90 seconds to load depending on the number of apps on your Android device. From here you an uninstall, clear cache, etc.. of applications.