Using simple or fancy search engines, one can search for your structure of interest.
Entries are added daily, so check often.
To view the structures, you can use a variety of free software . Rasmol is one of the older and still widely used programs, and is available on Mac, PC, and Unix versions. Those programs will let you rotate, color, and zoom on existing protein structures. You can also save images and save scripts which will get you to specific orientations, etc. A newer program, SwissPDB Viewer , similarly allows viewing structures and has a fancier interface.