I added a CSS Reset to the output from psd2css Online today. Just do your HTML, Drupal or Joomla conversion and you will get it automatically.
I've gotten a number of questions that boil down to different browsers having different default settings for some kinds of elements that you can put in your page. I've been frustrated occasionally too when the content of a _text layer doesn't line up exactly at the top due to a default margin on a paragraph element for a given browser.
A CSS reset script is intended to set all the CSS that is different between the various major browsers to something specific - so that there is a common starting point and your page will look the same on all browsers.
I implemented a slightly modified version of Eric Meyer's CSS reset found here: http://meyerweb.com/eric/thoughts/2008/01/15/resetting-again.
Please let me know what you think! Thanks.
--
Shaun
CSS Reset
I was just going to email you about Reset/YUI but you beat me to it :P