having problems extracting zip files on my new MBP

I downloaded a huge program that was broken up in small chunks in a zip archive. I want to be able to select all the pieces and unzip all of them at once in the same folder. When I try to do this it extracts each piece in separate folder. This was an easy thing to do on my PC using Winzip or Winrar.

How can I do this on my Mac?

Try this http://macupdate.com/info.php/id/11052/machacha

otherwise you will have to use the terminal

navigate to the folder with the files in it

type in: cat file1.zip file2.zip.002 file3.zip.003 > combined_zip_file.zip

Try StuffIt Expander?
http://my.smithmicro.com/mac/stuffitexpander/index.html