Apps are in their own folder.
To check where yours are stored, go to the first computer where your iTunes media is stored, and you'll find a folder called mobile applications. If you aren't sure where this is, find an app in iTunes and right-click.
In the submenu there's an option to see where it is located (both macs and PCs do this just with different words).
You'll have to copy the files for each app onto the new computer into the similar location, and then likely drag them into iTunes so iTunes knows they are there.
Hope this helps.