Yahoo has upgraded its HTML5 mobile web mail experience for the iPhone and iPod Touch, with a faster and more feature-rich version. It’s available as an opt-in trial, and has many of the same features as the desktop version.

Yahoo lists these properties of the offering:

• Faster and more reliable: If you’re offline, Yahoo! Mail uses local caching capabilities to help you access and search your messages even without an internet connection.
• Smart: You can find and organize your messages using Full Search, personal folders and Smart Folders with messages from your most important contacts and optimized views for photos and file attachments.
• Rich: View rich photo and video attachments in their full form, or as previews directly in the inbox view.
• Seamless & unified experience: Going forward, you’ll see a consistent look and feel, whether you’re on a smartphone or a PC.

The product is available in 28 languages and 200 countries. While it’s available as an opt-in beta right now, Yahoo says it hopes to upgrade all users shortly.

Yahoo has also released its first-ever Android apps – Yahoo Messenger and Yahoo Mail.