Given it's one of the most important new features of J2EE 1.4, I would expect several questions to appear... probably wrapped up in standard/custom tags as well! EL is not a difficult topic once you get used to it - it's a little like trying to pass a mini-SCJP exam in that you have to learn the syntax and operators carefully. Once that's done however, it should become much easier. I would suggest creating a few test JSPs and just trying ideas out - all you need to do is deploy and run a single JSP containing your EL test expressions.
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / AmazonAmazon UK )