If you come into a situation where you need to compare the settings of two Group Policy Objects without having to go through each screen one by one, then take a look at the following option to accomplish this.
Find the GPO´s you want to compare, right-click the GPO’s and save reports as XML
Launch XML Notepad and open the first GPO
Then click “View” > “Compare XML files…” select GPO to compare with
Then all settings which differ is marked with green.
Besides the above approach, I am currently only aware of 3rd party vendors who enables you to compare GPO´s, unless you use Microsoft Advanced Group Policy Management (AGPM) Which is a component of MDOP (Microsoft Desktop Optimization Pack). But if you know a smarter method for doing this in a 2003 environment please drop a comment