JSF and Jakarta Struts

Well, I'm new in java web technologies. All I know is JSP is like PHP that can be used to build dynamic pages. But I hear these words JSF and Jakarta Struts a lot these days. So, what exactly are these? Why use them? And what is a servlet? Want to see the big picture.
[ April 26, 2005: Message edited by: Mousa A. Rafi ]

Struts is a ofently used Controller for JSP applications that makes your application easier to build and control using an M-V-C layer separation approach.
Struts is used in conjuction with JSP to control the flow of the application from page to page and to execute backend code.

Here is a simple example of using Struts in an application:
http://www.oracle.com/technology/products/jdev/collateral/papers/10g/reviewer/viewlets/reviewer_struts_viewlet_swf.html

JSF is both a controller (like struts) and a better way to build Web UIs using components.
You can read an introduction to JSF and experience a simple tutorial here:
http://otn.oracle.com/jsf

[ April 26, 2005: Message edited by: Shay Shmeltzer ]
[ April 26, 2005: Message edited by: Shay Shmeltzer ]

I am new to this as well. If you use JSF do you need to worry about trying to implement Struts, or is the general functionality in JSF?