Google on Wednesday released a set of themes for Gmail, offering consumers using its Web e-mail service a chance to personalize their messaging environment.

"Gmail fans have been building unofficial extensions to spice up their inboxes for a while, but up 'til now themes haven't been an integral part of Gmail," said Gmail engineer Annie Chen in a blog post. "We wanted to go beyond simple color customization, so out of the 30 odd themes we're launching today, there's a shiny theme with chrome styling, another one that turns your in-box into a retro notepad, nature themes that change scenery over time, weather driven themes that can rain on your mailbox, and fun characters to keep you in good company."

Google's enterprise customers, however, are allowed no such levity: Gmail themes are not available to Google Apps users, a Google spokesperson said.

Google's personalized home page, iGoogle, has had themes for over a year.

To apply a new theme, select the Settings link in Gmail and click on the Themes tab. Those who don't have such a tab yet should see one in a few days, as the Gmail update propagates across Google's servers.

Gmail has been the focus of much attention from Google lately. Last week, Google added voice and video chat to Gmail. About three weeks ago, Gmail gained the ability to send and receive SMS messages, though Google temporarily withdrew that feature in order to fix a show-stopping bug.

Just last month, Google launched seven features for Gmail: Gmail Gadgets, emoticons for messages, Gmail for mobile version 2.0, Canned Responses, contact manager improvements, advanced IMAP controls, and Mail Goggles.