• Program name, e.g. CyberView Plus.
• Name of the person or company who wrote the program.
• logo.
• Program version e.g. 1.3 build 234. Don’t leave out the build. It can be very useful in tracking bugs.
• purpose, a one or two lines on what is this program for? e.g. word processor, XML verifier, shows you how to write Java code to do conversions, let’s you view *.jpg, *.gif and *.png image files. This information is for someone who stumbles onto the program and wonders what it is, should he keep it?, who might it belong to? Use the most non-technical language possible to describe the program.
• status, e.g. unregistered shareware, registered shareware, freeware, commercial, company confidential.
• release date e.g. 2004-05-17. This is far more useful to the user than the version for determining just how fresh his software is.
• copyright e.g. copyright (c) 1996-2008.
• masterSite URL, where to find the most up-to-date *.zip or *.jnlp, e.g. http://mindprod.com/products1.html#CONVERTER
• Company contact information possibly including mailing address, phone, email address and website. Customers will want to contact you about upgrades, replacement, bugs etc. Don’t hide on them. Give multiple avenues. All this information could change and you want to give the customer as many clues as possible to find you.

I use com.mindprod.common13.CMPAboutJBox to create the about dialog. It is part of the common13 package. You can download it, modify it and use it yourself.