DiffPDF is developed by Mark Summerfield, I just compiled it to windows 32 version.
DiffPDF depends on poppler, poppler-qt, Qt4 library.

DiffPDF can compare two PDF files. It offers two comparison modes: Text and Appearance.
By default the comparison is of the text on each pair of pages, but comparing the appearance of pages is also supported (for example, if a diagram is changed or if a paragraph is reformatted). It is also possible to compare particular pages or page ranges. For example, if there are two versions of a PDF file, one with pages 1-12 and the other with pages 1-13 because of an extra page having been added as page 4, they can be compared by specifying two page ranges, 1-12 for the first and 1-3, 5-13 for the second. This will make DiffPDF compare pages in the pairs (1, 1), (2, 2), (3, 3), (4, 5), (5, 6), and so on, to (12, 13).

It is open source(of course free software), want to try it on your windows XP/Windows 7, please download here.

I have installed QT4.6.3(2010.04, install path is D:\Qt\2010.04), and want to integrate mysql support into my new project, so I need to build qmysql plugin first.
prepare job,
download mysql-noinstall-5.1.49-win32.zip and unzip to D:\basetool\MySQL-5.1.49-win32
download mingw-utils-0.3 and unzip to D:\Qt\2010.04\mingw\bin

run Qt Command Prompt, and execute the following script
cd D:\basetool\MySQL-5.1.49-win32\lib\opt
reimp -d libmysql.lib
dlltool -k --input-def LIBMYSQL.def --dllname libmysql.dll --output-lib libmysql.a
copy libmysql.a D:\Qt\2010.04\qt\src\plugins\sqldrivers\mysql
cd D:\Qt\2010.04\qt\src\plugins\sqldrivers\mysql
set MYSQL_PATH=D:\basetool\MySQL-5.1.49-win32\
qmake "INCLUDEPATH+=%MYSQL_PATH%include" "LIBS+=-L. -lmysql" mysql.pro
mingw32-make
copy D:\basetool\MySQL-5.1.49-win32\lib\opt\libmysql.dll D:\Qt\2010.04\mingw\bin

Test the demo sqlbrowser(in the D:\Qt\2010.04\qt\demos\sqlbrowser), and works.

P.S.
first time I downloaded mingw-utils-0.4-1, and when run the command “reimp -d libmysql.lib”,I got the error message
reimp: libmysql.lib: invalid or corrupt import library
after search , I knew, have to use mingw-utils-0.3, the version 0.4-1 does not work and report the error message.