Added some more information on how the port works

README.android

@@ -10,6 +10,7 @@ http://developer.android.com/sdk/index.html
 Android NDK r4 or later
 http://developer.android.com/sdk/ndk/index.html
 
+
 ================================================================================
  How the port works
 ================================================================================
@@ -21,6 +22,16 @@ the SDL library
 Java project, along with some C support code that communicates with Java
 - This eventually produces a standard Android .apk package
 
+The Android Java code implements an "activity" and can be found in:
+android-project/src/org/libsdl/app/SDLActivity.java
+
+The Java code loads your game code, the SDL shared library, and
+dispatches to native functions implemented in the SDL library:
+src/SDL_android.cpp
+
+Your project must include some glue code that starts your main() routine:
+src/main/android/SDL_android_main.cpp
+
 
 ================================================================================
  Building an app
@@ -48,11 +59,11 @@ android-project/
 	build.xml		- build description file, used by ant
 	default.properties	- holds the ABI for the application, currently android-4 which corresponds to the Android 1.6 system image
 	local.properties	- holds the SDK path, you should change this to the path to your SDK
-	jni/			- directory holding native code and Android.mk
+	jni/			- directory holding native code
 	jni/Android.mk		- Android makefile that includes all subdirectories
 	jni/SDL/		- directory holding the SDL library files
 	jni/SDL/Android.mk	- Android makefile for creating the SDL shared library
-	jni/src/		- directory holding your application source
+	jni/src/		- directory holding your C/C++ source
 	jni/src/Android.mk	- Android makefile that you should customize to include your source code and any library references
 	res/			- directory holding resources for your application
 	res/drawable-*		- directories holding icons for different phone hardware