To enable this feature, within Gmail click on Gmail Labs (either the tab or the green beaker icon) and click “enable” under Translation. When Gmail detects one of your messages is in a language other than your default language, you’ll see a header at the top of the message. Click the link that says Translate message to…. Your message will be translated inline (no need to open a new tab or window).
In other Apps related news, Google has made some big updates to Google Sites including allowing for hierarchical navigation of your Site’s pages, refreshing the edit menu to be more consistent with Google Docs and switched the site settings area to vertical navigation to prepare for upcoming features, one of which, according to Jens Alfke of Google, is Google AdSense integration.