I used several books. The one I found to be extremely helpful are the "Exam Cram" series. My recommendation is to go with the Exam Cram, read it, and then go through an entire study guide on the A+. Memorize IRQ tables, I/O addresses, microprocessor features, identification of RAM, calculation of hard drive size, and especially printer theory/troubleshooting. After that take a good number of practice tests. For me I went through about 1900 pages of material before I took the test, but that's what worked for me.
Gary
gwinn7
A+, Network+