Samsung has yet to reveal the Galaxy Note III, however it looks like some accessories have already come available for purchase. These aren't official Samsung products and that does give us some reason for hesitation, but two Galaxy Note III accessories have recently been spotted on Amazon from two different sellers.
The first of the two is a case. This one is pictured above and as you can see, it is just your basic style skin. This one comes by way of InventCase. The second is an extended battery and it comes by way of Hyperion EA. This one is a bit more interesting as it claims the battery supports the Verizon, AT&T, Sprint and International Note III. Notably missing from that is T-Mobile.
It is also slightly interesting that there was no size mentioned for that extended battery. Putting those details (and lack thereof) to the side -- while both of these are available for purchase neither are shipping at the moment. In fact, both of these accessories are sitting with a "usually ships within" time of 3 to 5 weeks.
As we know, Samsung will be announcing the Galaxy Note III (and the Galaxy Gear) on September 4 so we would suggest holding off any any accessory purchases until at least that time. We will also be looking towards that September 4 event to see when the handset will actually be available. Recent rumors have suggested a potential date of September 27.
Otherwise, just in case anyone needed any reminder about the Galaxy Note III announcement date, the folks at Spigen have recently published a reminder. That reminder has a rendered image along with text that makes it all pretty clear by stating that the "Galaxy Note III will be announced on Sept 4th." As for that event, we will be live on-site in Berlin to bring the latest news on September 4 and through IFA.