I've used many mind mapping tools and find them lacking in functionality (xmind) , expensive (inspiration) or very hard to use (Free Mind). Most of these tools will not allow you to have 2 main topics and create a double bubble map (like a venn diagram). Edraw Mind Map has a very easy to use ribbon interface similar to Word 2010 and tons of built in symbols and mind mapping templates. It is free for educational use and their site has tons of video tutorials that cover all the nifty features. It's the first mind mapping program where I felt like I wasn't fighting the interface.
Three tools Thimble, X-ray Goggles and Popcorn Maker allow students to explore HTML and CSS and author web pages simply. Fantastic examples of online web applications.
A fantastic free quarterly e-science education magazine and some school science resources from the University of Adelaide. The Magazine is available as a free iPad version which is excellent and includes class resources (videos, audio, worksheets) to bring it into the classroom. Highly recommended.
A great list of recommended reading compiled by Expeditionary Learning, a site committed to developing schools which focus on student driven learning experiences.
A free design course to encourage programmers/hackers into developing solid design skills, but most of the content is relevant to anyone wanting to improve their design skills (covers design in general including industrial design, web design, UX, etc). Some excellent resources are already available.
A toolkit that encourages educators to design solutions to workflow problems in the classroom, which in turn will help students and teachers understand the process of design thinking as used in business. An excellent resource with inspiring videos.
An intelligent textbook for iPad being developed. Kind of what I thought the disappointing iBooks platform was going to be about. Is this the future of textbooks?
An excellent adaptive learning site that provides online tutoring, interactive tools, and challenges in a fun and engaging way. Students need to use "yoops" (a virtual currency) to progress through activities. This does eventually require students to pay their way through the course as free yoops become increasingly difficult to acquire.. which is the largest drawback.