I am going to show you how to install some portable applications on your usb drive, the apps can be found at portableapps.com
but i have uploaded a basic starter kit for you.
I recommend a 1GB minimum, i picked up this PNY 2GB usb flash drive at my local tesco today for only £1, yes you heard me correct £1!
PS. my first instructable so sorry if im unclear on the steps