Portlets .....How / Where / When to start ?

Can anyone answer my below questions please ? I am waiting to start on it.Thanks.

Hi Ranchers ,

I have been a Java Programmer for over a year . My main tasks in my Job include coding JSP`s and Servlets . I want to learn IBM portlets . My colleague told me that the market for this is very good in the US and ofcourse good billing . Can anyone answer my below questions ?

1) What exactly are Portlets ?
2) What are its prerequisites ?
3) Does my JSP`s/ servlets knowledge help me ?
4) How difficult it is to learn this ?
5) Can anyone suggest me any books to learn the Basics of Portlets ?
6) How should I go about to do any certifications ? I know we have an IBM certification .
7) How is the Job market for this?

Can anyone who is working in this technology help me by answering my above questions in detail ? I would really appreciate their help .

Thanks in advance.

[ October 30, 2007: Message edited by: Rakesh Yelugoila ]

just do google search and you will get lots of sites which gives all the basics of portlets/portals

IBM Portal
http://www.ibm.com/developerworks