I have recently been looking at the breakdown of one of my apps on ANdroid Market, and was surprised to see that a number of downloaders were using Galaxy Tabs and a few oth
You can use the <compatible-screens>
element to prevent, for example, devices with x-large screens from seeing your app in Google Play.
http://developer.android.com/guide/topics/manifest/compatible-screens-element.html
<supports-screens
android:smallScreens="true"
android:normalScreens="true"
android:largeScreens="true"
android:xlargeScreens="false"/>
But I suspect that it will prevent your app to run on Galaxy Tab but you can gave it a try
This question has been going around a lot recently and it seems that you cannot stop people from downloading and installing your app based on their device-type.
A couple things you can try are: