@Abdullateef > I would never recommend anyone MIDI map a Pioneer DJM mixer because the mixer hardware is superior in quality to the software capabilities.
That being said, the only thing you should really look into doing, is connecting your CDJ's with VDJ.
Overall, Rekordbox is the free software that came with the CDJ-2000's and is also available online for free from Pioneer. Rekordbox allows the CDJ-2000's to be used to their full potential and I would highly recommend trying Rekordbox and seeing it's capabilities before using a DJ software application.
If you still feel the need to get VDJ running with your CDJ-2000's, you will need to first set up an "aggregate device" on your Mac, then make sure you connect your CDJ's to your computer via USB cable, and have your other audio cables connected from your CDJ's to your mixer. You will then need to configure your CDJ's in Virtual DJ and make sure you select the aggregate device you created earlier, as well as the proper sound card, and the proper inputs/outputs within VDJ.
An easier method for creating an aggregate device with your Mac, you should download the "Mac OS Tool" from Pioneer on this page: http://pioneer.jp/support/download/dj-e/cdj-2000/
Personally, I think you should use Rekordbox and not bother with another type of software at this time. But if you feel it's really necessary, then feel free to set it up with VDJ Pro.
Don't forget to search these forums first for similar issues if you run into problems in the future. ;) If you can't find what you're looking for or not sure if the issues are related, just start a new thread. You could also continue posting in this thread if you would like. :)