Is there any IDE+Emulator for developing Andriod App?

You can use Eclipse and download ADT plug-in for developing Android Application

Coming to Emulator.... its is already included in SDK

Eclipse is a good IDE to use for development.

Android development is probably easiest on Eclipse, but you can use other IDEs too, they just take a little more setup. Have a look at the Developing section in Android developer guide.

Intellij IDEA also has a plugin for Android, but I had trouble using it, and found it easier to just use the Ant build file created by activitycreator tool.

The recommended way to develop an Android application is to use Eclipse with the Android Development Tools (ADT) plugin, provided in the SDK. The ADT plugin provides editing, building,and debugging functionality integrated right into the IDE.

However, if you'd rather develop your application in another IDE, such as IntelliJ, or use Eclipse without the ADT plugin, you can do that instead. The SDK provides the tools you need to set up, build, and debug your application.

Two IDEs:

Eclispe with the Google ADT plugin

NetBean with the nbandroid plugin

Here is a very detailed and easy to follow step by step guide for setting up everything you need to get started.
The tutorial will show you how to install and configure

Eclipse 3.5

Android 2.1 (Android SDK rev 4)

JAVA (JDK 6 Update 18)

Setup virtual device

Then follow the Hello World tutorial at the same blog.

[Tutorial] Step by Step Guide to Setup Eclipse and Android 2.1 SDK

My buddy has a great how-to for setting up the development environment and your phone to allow real-time debugging:

Android Development Blog: http://goo.gl/lbH9

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