CSS/XHTML coding: Need this newsletter box coded

I need the following image coded in valid CSS/XHTML (please check Browsershots after you're finished for browser compatibility). The inspiration for the newsletter signup box comes from RedCrownStudio, so you can see how the code is coded on redcrownstudio.com. Please note: Please only use the XHTML code provided, and not modify that XHTML file. All you're doing is editing the CSS file, and inserting the submit image button.