You can download the Eclipse 3.1M6 or M7 'http://www.eclipse.org/eclipse/'

or

Netbeans 4.1 'http://www.netbeans.org/' Java development IDE's.

Eclipse has a plugin for Tomcat you can install, real easy.

Netbeans comes with its own embedded Tomcat so you can test your servlet
development on that. I am a big fan of Eclipse but NetBeans has all you
will need in one download. It also has JSP and Servlet samples in the
IDE's Welcome Page that will help out your leaning process in one Download.

As far as all of the acronyms. For what you need is just the JDK 1.5.0
this is the java developer kit software. The JRE is the java runtime
environment and comes bundled with the JDK 1.5.0 This holds all of the
classes you will need to run your java programs.

You do not need J2EE for what your will be doing. To use the J2EE 1.4
You would need a J2EE 1.4 compliant application server like Sun's
Application Server or JBoss  or others. For what you initially want to
do you do not need it.

You are not alone. It is confusing, and documentation is sparse.

Tomcat is easy to install... There's nothing to install, just unzip
and its ready. To integrate with Apache, you have several options:

1. mod_jk. go here and install:
http://www.apache.org/dist/jakarta/tomcat-connectors/jk/binaries/

2. mod_proxy: easiest method if you just need to host simple servlets

3. Use Tomcat as standalone. By default, it listens to port 8080, but
it can be changed.

You are not alone:
JRE: Java Runtime Environment. Required for running java programs.

j2sdk:  Java 2 SDK. Includes JRE. Required for compiling java
programs.  1.5 is the same as 5.0. Sun didn't do itself any favors
with the number debacle. Same thing happened when 1.2 (Java 2) came
out...

You need the j2sdk. Probably 1.5.
Get Tomcat.

--
now with more cowbell

I've worked in the computer industry for 20 years. I dealt with acronyms
all my career but never as many as when I got into Java and J2EE.

A quick history. In the beginning there was Java and it was good. The Java
Development Kit (JDK), also called the Java Software Development Kit
(SDK), was originally called the JDK. They made some significant chances
to it. The developers dubbed this Java 1.2 and marketing decided to call
it Java 2.

Later they started calling Java 1.2 and older J2SE. I'll get to that a
little later. Just remember that when people talk about Java 1.2, Java 2
and J2SE they are talking about the same thing.

Over the years there has been version 1.2.x to 1.4.2. These are all J2SE
or Java 2.

Recently, they made some significant changes again. The developers called
it Java 1.5. Marketing, just to be different, are calling this Java 5.0.

That is pretty much all you need to know about the version numbers. Next is
the difference between SDK and JRE. J2SDK is the Java 2 SDK; SDK is
Software Development Kit. It is also called the JDK for Java Development
Kit. If I want to write Java programs I need an SDK. The JRE is the Java
Runtime Environment; if I want to run a Java program I need a JRE.

So SDK/JDK/J2SDK are needed for writing Java programs. JRE/J2RE are needed
to run Java programs. NOTE: if you have the SDK then you also have a JRE.

If you have the disk space get the JDK, even if you just need to run Java
programs.

The majority of people are stilling using 1.4.2 or older. If you want to be
leading edge then get the 1.5.0_03 SDK.

The final set of acronymns you will have to deal with is J2SE, J2EE and
J2ME. J2SE is the original Java. It stands for Java 2, Standard Edition.

J2EE is Java 2, Enterprise Edition. This is for people programming
applications for servers. This is what you are looking for. You might also
need the J2SE as well as J2EE builds on J2SE. I think J2SE is bundled with
the J2EE downloads.

J2ME is Java 2, Mobile Edition. This is a scaled down Java. It is scaled
down so it runs more efficiently on mobile devices, like cell phones.

Hope my message helped. Just so you know, I install an application server
(like Tomcat or JBoss) and do all my development there. Once I have my
servlet working on the application server I then configure the web server
(e.g. Apache) to work with my application server. For example, I might have
my servlet running at http://localhost:8080/MyFirstServlet. Once I have it
working, I'll configure Apache to redirect
http://localhost/WorldGreatestServlet to the application server at
http://localhost:8080/MyFirstServlet

This book is the answer.
It walks you through it from start to finish.
http://www.murach.com/books/jsps/index.htm