What is the easiest way to use XML-RPC in android? I tried http://code.google.com/p/android-xmlrpc/ , but it dooesn't compile and looks abandoned.
You can take a look at how the WordPress client for Android is doing it. The code is public under the GNU General Public Licence and can be inspected via SVN here: http://android.wordpress.org/development/
The client itself is implemented in the package org.xmlrpc.android
essentially using Android provided libs, like e.g. the XmlPullParser: http://developer.android.com/reference/org/xmlpull/v1/XmlPullParser.html
It's not as simple as sticking a jar into your project, but it seems to be a lightweight path to explore. And it certainly works as the WordPress client is under ongoing development and use.