Phishing involves an attempt to obtain your personal information through a website or email that appears to be from a legit organization. Due to technological advancements, the process has been made much easier and much cheaper. Phishers (people who phish), make very good imitations of online banking sites and also employ various tricks to make their site more believable.
Various methods employed include link manipulation in which the links used to send the victim to the "proper" page is altered. Other methods include "Man-in-Middle", which allows the phisher to test the legitimacy of the victim's input (making the site seem more genuine) and using multiple windows to conceal the genuine website and launching a page to collect infomation.