Ubuntu 12.04 from USB

First time I have installed Ubuntu from USB.
1. downloaded the .iso file from here
2. made a copy into the usb drive
3. MOST IMPORTANTLY created the bootable USB drive using usb-creator.
(If you don't have the package then install it from Synaptic Package Manager.)
     -open up the Synaptic Package Manager
     -search for package usb-creator
     -Go to System - Administration - Startup Disk Creator (linux 12.04 version)
     -Show the source file path and destination drive

All set to install.

Useful reference

Problems: If GRUB is missing then use the following solution.
                 Initially started by downloading the 32 bit version. And formatted the usb using FAT. Did not work. Later installed the 64 bit version using the NTFS formatted flash drive.