Here are 9 sites where you can discover interesting mindmaps on the web. Some of them are hand made other ones computer made. Mind Mapping Software companies like Mindjet, NovaMind or Xmind have created their own sharing sites where you can find and download mindmaps in their proprietary formats. Biggerplate is specialized in Mind Manager mindmaps. Mindmap Art is a place where you can discover beautiful hand made mindmaps.
I used Pearltrees, a social bookmarking service, that allows you to create interactive and collaborative mindmaps, for sharing those links.
Browsing the mindmaps search on Flickr, I found those excellent hand made mindmaps, created by Mie Kaieda, Web Designer/Director based in Tokyo, Japan.