That's right kids, it appears that some anonymous donor has bequeathed the 24 pages of original 1962 Steve Ditko pencils from Amazing Fantasy #15, to the Library of Congress in Washington, D.C. As we all know this is the very first appearance of the world's most famous web-slinger, Spider-Man. As stated, the pages are Ditko's originals, complete with pencil erasures and white-out opaquing fluid.
For the full story, you can go here
Some images of the art appear here, but if you follow the link and click on the images in the story you can see them much larger.
As a follow-up to this story, it appears that it was the entire contents of Amazing Fantasy #15 that was donated to the Library of Congress, and the individual making the donation, apparently checked with Steve Ditko prior to making the donation. Included in the donation were the pages for the three monster stories were in the book; "The Bell-Ringer," "Man in the Mummy Case," and "There are Martians among us!"