Importing image folders into Adobe Bridge
Bridge is just a folder browser, so technically you don't import anything into it. You give it a folder, it shows you what's in it, kinda like the Finder. The reason Adobe makes it is so you can do Adobe things you can't do with the regular Finder like open directly into Camera Raw. It does have a camera downloader, which copies camera images onto your regular hard drive folders where you can find them on the desktop. It will display them in Bridge just because Bridge hosted the camera downloader.
I am not an Aperture user but I know you have two choices as to how to store your photos with Aperture. Either you had Aperture "manage" them or you left them in regular desktop folders and have Aperture simply "reference" to them. If you referenced them, all you have to do is point Bridge there (or drop the folder on the Bridge dock icon) and you'll see the images in Bridge. If you have Aperture manage them, it's tougher because the masters are hidden. I would like to say you can do a Show Contents and drag that into Bridge, but I may be wrong and it might cause problems so an Aperture user should answer this for you.