i want to know what IDE, basic knowledge of language is needed for development of android apps?

I recomend using eclipse with Java, you could also use C++ with eclipse but there isnt so much reference in c++, now in Java theres alote of reference available in google or you coul use C# with Mono. You could start with this reference to intall the android SDK with eclipse: http://www.talkandroid.com/guides/developer/android-sdk-install-guide/ , its free. Now if you whant to waste money you could buy a Mono License and program in c# .NET http://xamarin.com/monoforandroid

Eclipse is by far the best tool right now to use but you should keep an eye on android studio because even though it is still a work in progress it looks like it will be a very promising IDE and similar to eclipse in many ways. http://developer.android.com/sdk/installing/studio.html

@bCubed I'm gone be cruel but you been living under rock. Eclipse lost profesional developers support+interest+appeal over last 2 years because of the never ending issues with Maven support and proper application testing and people slowly moved to IntelliJ.
Android Studio is gone be nothing like Eclipse, because Android Studio is based on open source version of IntelliJ. On top of that Android Studio is designed with Gradle as top priority

I also recently started working with Android, I tried Eclipse and Android Studio. I must say I much prefer Studio.

Eclipse was really good when I was only using standard Java but once I started adding pluggins into the mix I started getting several issues and as such I swapped to IntelliJ Idea.