Doraemon is to Japan, as Mickey Mouse is to the U.S.
That's a pretty good comparison. The only other character in Japan that even comes close to his popularity is probably Astro Boy....and that's by default.
OK, now a little info. Doraemon was the creation of two mangaka who both went under the pen name Fujiko Fujio in the late 60s. Both artists had already been participating in the manga industry for about 10 years before there brainchild finally came to life. However, the actual character didn't become a household name until 1980, when the Doraemon anime premiered on television and became a nationwide smash. Before then, Doraemonhad only been in print form (the exception being a failed anime in 1974)
Now, for the story. In the 22nd century, robots have become commonplace. Among these robots is a little blue robot cat named Doraemon (pronounced doe-ry-mon). Doraemon is a failure in everything, ultimately failing his exams in robot school and being bought by a poor family.
However, the family do infact find a useful task for him to perform. It turns out that the reason for the family's poverty is due to the mountains of debt that the family father's great-great-great-great-grandfather, Nobita, left as his legacy. So, they decide to send Doraemon back in time to when Nobita was still a child, so as to help him succeed in life and not become a failure in the future.
Now, here's what makes Doraemon cool. The robot cat has a little pocket in his stomach called a 'fourth-dimensional pouch'. With this pouch, he can produce a bevy of futuristic gadgets. Including such things as air guns, rockets, time portals, and even a little propeller beanie that can be used to fly.
Now, mind you. The men who made up the Fujiko Fujio duo were not the most detailed manga artists in the world. And, like Tezuka before them (and Toriyama after them), there comics were largely aimed at children.
However, what makes Doraemon so awesome is its simplicity. Because of the simple plots and character design, Fujiko Fujio were able to parody and give homages to ALL KINDS of things, from Star Wars and Arabian Nights to Journey to the West and Astro Boy. Doraemon's simplicity is his greatest asset, and why the plots were ALWAYS refreshing.
Sadly, Doraemon has never been made into an english only edition. HOWEVER, there have been several bi-lingual editions published by Kodansha, printed in both English AND Japanese. They're loads of fun, and a good way to learn the languages.
If you have never experienced Doraemon, you are in for a real treat.
