There's been a lot of discussion of using C or C++ and there's no reason that you cannot. Someone would just need to create a compiler that converts the C code to Dalvik byte code. At the moment, it does not exist and you are stuck with Java.
Installing the Android SDK + Eclipse IDE is a piece of cake and the instruction can be found here:
Setting Up the ADT Bundle | Android Developers
If you know how to make web applications/web sites... you can use those skills to make Android apps. Start here:
Apache Cordova and here:
PhoneGap | Home
The Facebook app used Cordova. Find out who else did here:
Who Uses PhoneGap/Apache Cordova? | ANDREW TRICE