What programming language should I teach my little brother?
seshagiric: at 13 your brother need not worry about memory leaks :) 
Just let him start with C.More importantly you should concentrate on what can be done with code(e.g. create a blog, automatically search from library of congress or wikipedia, create a graph of his favorite football team etc etc).People get hooked when they accomplish something...bothering about language or the finer nuances like memory leak etc can come later.