1. Download
Download link: http://netbeans.softonic.com/linux
The downloaded file’s name:  netbeans-6.8-ml-linux.sh

2. Install
GO to the directory where you downloaded it. I have it in Desktop

$ cd Desktop

Installing

$ sudo sh netbeans-6.8-ml-linux

Accept anything and click all NEXT buttons that show up in the screen

3. Run Netbeans
Go to this directory

$ cd /usr/local/netbeans-6.8/bin/

Run netbeans

$ ./netbeans

That is all!