My book How to Think Like a Mathematician is available and currently selling well - it is regularly in Amazon's chart for the 100 best-selling mathematics books.
You can buy it at Amazon.co.uk, Amazon.com (in dollars), Blackwells online, from the publishers Cambridge University Press, and from almost any online bookshop. These links will take you to the paperback version. A hardback version is available.
A Turkish version is available.
Solutions to How to Think Like a Mathematician
Chapters 3 and 4 on writing mathematics were (more or less) put into a booklet for our students here at the University of Leeds:
Sample Chapters of How to Think Like a Mathematician
You can also see sample chapters at Amazon and at the publishers CUP, see the links above.
Some parts will be produced before terms starts here on 22nd September 2010 and more will follow after that.
Here is another demo video. It has a connection to How to Think Like a Mathematician in the sense that the mathematics behind perfect shuffles is modular arithmetic which is covered in Chapter 29 of the book. Comments are of course welcome.