I have started developing programs for Android.
The official web page of Android is:
The tutorial of the official web page is quite good.
I recommender you to read at least the "What is android". The second article, "Application fundamental" is fine too, but it´s very specific and long.
If you just want to start develop applications for Android and see how it works, you can do the example of "Hello world", which shows you the basic steps.
Update1: I found another tutorial which is more visual.
Also this tutorial is quite complete. It has the same style as this blog: Easy and fast:
Update 2: Video from robertMacHales
The video of this guy is quite ok for beginner. It explain everything with a lot of details.
Here is the first step: