This is a step by step w/pictures tutorial which may take almost half an hour if your kinda slow. So I suggest you get a full cup of coffee.
Installing Eclispe and Android SDK
Step 1: Download Eclispe and Android SDK below from the following sites:
Step 2: Extract both zip files
Step 3: Double Click on eclispe and what for it to load up
Step 4: Select a workspace
Step 5: Lets Install the ADT Plugin
Go to Help > Install New Software
Step 6: Click Add, in the top-right coner
Step 7: Fill in the information as follows and click OK
Name: ADT Plugin Location: https://dl-ssl.google.com/android/eclipse/
Step 8: Tick the Checkmark box for Developer Toolsand select Next
Step 9: Select Next again.
Step 10: Read and Accept License and hit Finish
Step 11: If you get a security warning saying that the authenticity or validity of the software can't be established, click OK.
Step 12: Select Restart Now
Step 13: As you can see we have avd and sdk in eclispe!
Step 14: Select Android SDK Manager
Window > Android SDK Manager
Step 15: Tick the Tools and Android 2.3.3 Checkmark boxes and hit Install
Creating a Android Project
Step 16: In Eclipse, select File > New > Project
Step 17: Open the Android Tab and Select Android Project then hit Next
Step 18: Name the Project Name: HelloWorld and hit Next
Step 19: Select Android 2.3.3 and hit Next. I have different Android versions because I installed more than 1.
Step 20: Change the Package Name to:
Editing the Application
Step 21: Open the tab HelloWorld > res > layout > main.xml . So once you open main.mxl, you will see the layout of the app.
Step 22: Start chugging on your coffee, I forgot I had coffee with me.
Step 23: Choose Screen Size, in this case I have an hvga device. Chose which fit your phone.
Step 24: Select main.xml tab and change verticle to horizontal
Step 25: Connect your phone to computer. Make sure USB Debugging is checked.
Step 26: Press Ctrl+F11 and select Android Application then hit Ok
Step 27: Congrats! You now created a HelloWorld Application!
Just watch this badass video, much easier