To uninstall apps that you installed, go to the menu, then to settings, then applications, then manage applications, then tap the app you want to remove, next a screen will pop up with the option to uninstall.
Some apps, however, are rooted to the phone and require more work to uninstall. For more information on this topic, I found this forum helpful: http://androidforums.com/samsung-moment/27666-how-delete-applications-phone.html
Hope this helps!