In this post I'll talk about how to set up your development environment for Android.
1. Download Eclipse ADT with Android SDK for Windows here. You'll realize that there are two full-featured IDEs you can use for Android development, Eclipse ADT and Android Studio. Android Studio is still in beta so I'd recommend the former. I haven't yet tried Android Studio, but after reading this post on the differences between Android Studio and Eclipse I just might.
Question: What's the difference between Eclipse and Eclipse ADT?
Eclipse is an open-source IDE, mostly provided in Java. Eclipse ADT is developed by Google and is a plug-in for Eclipse specifically designed for Android development.
2. Unzip the downloaded file and launch Eclipse from adt-bundle-<os-platform>/eclipse/
Having problems unzipping the file using the default unzipping tool in Windows? That's because the tool doesn't work when the file path is too long. Move the zipped file to the root of C:/ before trying again, and the problem should be fixed.
3. Just click OK when the prompt on selecting your workspace appears. Awesome! You're in Eclipse and can start writing Android apps right away!