Thanks, Bob. It seems ridiculous to me that I cannot find an application to create many different types of archives, but there is one that can extract from many different archives. I have one app that can create gzip, bzip2, zip, dmg, stuffit, and stuffit X archives. There is another one that creates tar.bz, tar.gz, zip, dmg, and dmg-bz2. Another app creates 7z archives, and another creates rar archives. Why do I have to have so many? Is it easier to unarchive than to archive?
If I just want to see inside an archive and maybe extract one file, I found only 2 apps that can do that: Jar Inspector and Better Zip.