This is the time taking and tough part while learning J2EE. For me It took 2 days to figure out which version to download and setting environment variables. My installation failed so many times for various reasons like I did not changed the port number to 8888 first time so when i open the tomcat link with 8080 I saw oracle server page and while setting environment variables. Finally I successfully installed and configured it. Below are the steps for tomcat installation.
1) Download Apache Tomcat5.0(good for beginners)
click on Jakartha-Tomcat-5.0.28.exe and install it.
During installation change port number to 8888 since oracle HTTP server run on port 8080 and if you already has Websphere it will run on 9080.
2) Set environment variables like this
right click myComputer–> properties –>advanced->environment variables->user variables
JAVA_HOME=C:\j2sdk1.4.2_08\ –> Give the JRE or JDK Path in your machine
PATH=C:\j2sdk1.4.2_08\bin; JRE or JDK path on your machine
TOMCAT_HOME=C:\Program Files\Apache Software Foundation\Tomcat 5.0
CATALINA_HOME=C:\Program Files\Apache Software Foundation\Tomcat 5.0
CLASSPATH=C:\Program Files\Apache Software Foundation\Tomcat 5.0\common\lib\servlet-api.jar;c:\ojdbc14.zip;
3) Right click on the tomcat icon in the system tray -> start service. otherwise start it from start->programfiles menu. Test the installation by giving the url
http://127.0.0.1:8888 in browser . it must open tomcat welcome page.