Here's a quick 'n' easy version of another post that uses the rpm instead of the extracting to opt.
wget http://download.oracle.com/otn-pub/java/jdk/6u25-b06/jre-6u25-linux-x64-rpm.bin
chmod +x jre-*
sudo ./jre-*
sudo alternatives --install /usr/bin/java java /usr/java/jre1.6.0_25/bin/java 20000
sudo alternatives --install /usr/bin/javaws javaws /usr/java/jre1.6.0_25/bin/javaws 20000
sudo alternatives --install /usr/lib64/mozilla/plugins/libjavaplugin.so libjavaplugin.so.x86_64 /usr/java/jre1.6.0_25/lib/amd64/libnpjp2.so 20000
Enjoy.