Android applications are written using the Java programming language.
Android only supports applications written using the Java programming language at this time.
No. There is currently only an Android SDK for the Windows, Mac OS X(intel), and Linux(i386) platforms. The SDK includes a software emulator on which you can test Android applications.
Please see: http://code.google.com/android/adc.php and http://code.google.com/android/adc_faq.php for more details about the Android Developers Challenge.