>Hi! Does anyone knows where I can buy a book to help me with the exam 70-155 on Visual Fox Pro 6.0. I tried on Microsoft but it says "out of print"
>I tried Amazon, B&N and google.com and nothing.

You can get it two places
http://www.amazon.com/exec/obidos/ASIN/1930919042/
http://www.hentzenwerke.com/catalogavailability/certfox6.htm

>I want free demos to practice. Thanks very much!

There isn't a demo for the exam. The book has 1 or 2 sample questions at the end of each chapter.