I have written an open source textbook covering calculus, functions of a complex variable, ordinary differential equations and partial differential equations. Many of the exercises are solved in accompanying Mathematica notebooks. The textbook is freely available for download in PDF and postscript formats from:
By "open source" I mean that the LaTeX source as well as the XFig files and Mathematica notebooks used to make the graphics are available. This is useful for those who want to "cut and paste" portions of the text to make their own documents.