Here is a short tutorial on how to install all you need for Android development on a Mac.

1. Download Eclipse 3.2, 3.3 (Europa) for your Mac on:
http://www.eclipse.org/downloads/

2. Download the Android SDK from here:
http://developer.android.com/sdk/index.html

2. Once you installed the SDK you can get the latest update from this command-line command by
executing:

tools/android update sdk

3. Install the ADT plugin
- Start Eclipse, then select Help ]]> Install New Software…
- Click on add and the window below will appear. Input the URL https://dl-ssl.google.com/android/eclipse/. Use http if https does not work. Name it “ADT Plugin”.

android_adt_plugin

- Click on Next, and then Next agian and accept the license agreements. Click on Finish.
- Restart Eclipse

4. Create an AVD Manager
- In order to run our Android app on the Mac we need to set up an Android Virtual Device in Eclipse.
Window > AVD Manager
- Create a new AVD by clicking on new
- Type in the name of your avd, in my case my_avd
- Choose a target.
The target is the platform (that is, the version of the Android SDK, such as 2.3.3) you want to run on the emulator. I chose the latest one I got.
- Click create!
android_virtual_device_manager

5. Now you are up and running!
Why not start with a simple Hello World:
http://developer.android.com/resources/tutorials/hello-world.html