Google Blogoscoped has got reliable information that Gmail will support themes in the coming months. He has also mentioned that there will be 12 themes to start with like a black-and-green “terminal” view, as well as a flowery view. There are already many ways to customize the look of Gmail with third-party tools like GreaseMonkey or custom user stylesheets.
Recently Google had added theme for iGoogle, now lets wait and see if Google adds themes for Gmail.
