How do you make a LinearLayout scrollable?

Wrap the linear layout with a <ScrollView>

See here for an example:

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout 
       android:layout_width="fill_parent"
       android:layout_height="fill_parent"
       xmlns:android="http://schemas.android.com/apk/res/android">
       <ScrollView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">
            <LinearLayout 
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:orientation="vertical">
                  <!-- Content here -->
            </LinearLayout>
      </ScrollView>
 </LinearLayout>

Note: fill_parent is deprecated and renamed to match_parent in API Level 8 and higher.

<ScrollView 
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/scroll" 
      android:layout_width="match_parent"
      android:layout_height="wrap_content">

      <LinearLayout 
            android:id="@+id/container"
            android:orientation="vertical" 
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
      </LinearLayout>

 </ScrollView>