From the introduction to Unofficial Texinfo Format:

Things go in spirals. We explored the powers of Texinfo and LaTeX at typesetting the PDF book. Now it’s time to come back to HTML. This year it shall be HTML5. “It can be a dangerous place, but it’s our last, best hope for peace.” (Sinclair, Babylon 5.) Does the peace endure after the browser wars? Anyway, the aim of the project is to approach the quality of LaTeX output by using the HTML5 toolbox. JavaScript, CSS3, SVG, MathJax, MathML, and web fonts are employed here. Due to the experimental nature of this enterprise, there will be glitches and errors in some browsers. Technical and artistic help is appreciated. In the meantime, enjoy the book, and fire up a REPL!

For online reading: web version
For offline reading: epub
Source repository: sicp

There are only a few apps that render the epub3 version fairly, but still not correctly. Readium, Azardi Desktop, and iBooks are almost there. While we wait for the other readers to mature, we can read the HTML5 version in a browser (tested in latest Firefox, Chrome, and Safari).