De,
What operating system are you installing onto. That is probably the first and most important question.
For JDK 6 with
Java EE you probably want this link
http://java.sun.com/javase/downloads/index.jsp and then "JDK 6 Update 12 with Java EE". From there you can select your platform and language.
For Tomcat 6 You'll want this link
http://tomcat.apache.org/download-60.cgi and probably one of the binary distributions. I believe both Windows and Linux are included in the same zipped files, i.e. Linux uses shell script and Windows uses .bat files in order to start tomcat.
For installing you can read the documentation from each site, but for linux I like to use
http://www.howtoforge.com . They really have a great community and plenty of installation walk-throughs.
good luck!
Brad