Ez7z is a compression application made by Leif Heflin for Mac OS X that handles .7z, .bz2, .rar, .zip, .par2, .gzip, .tar, and .001 files.
There are five actions possible: expand, shrink, view, delete, and par2. Deleting refers to deleting a file within an archive, without extracting it first.
Drop any number of items onto the drop box in the main window and set them up to be processed in the time it would take to set up one file.
Once the processing has started, you can uncheck a checkbox in the process window and it will auto-advance to the next file when its done with the current one.