Gmail has updated its iOS app with a few small features it was lacking at launch, most notably the ability to add a custom signature for messages sent from your mobile and settings for enabling a vacation responder.
The mobile signature is great if you want to add a note to the end of your signature stating that you're mobile, and the vacation responder is handy if you aren't bringing your computer on vacation. You can hit the new gear icon above the sidebar to access these features.
Other updates include better support for nested labels and a fun "Scribbles" feature that lets you make hand-drawn images using the touch screen to send in your emails. Google says it has also fixed a number of bugs and UI issues, though it hasn't fixed any of the issues that makes it a mediocre app. Hit the link to read more.
Note that if you're already using Gmail for iOS, you may need to uninstall the app and re-download it manually. The Lifehacker staff had some trouble when updating it from the App Store; it didn't give us the new version -- just a buggier copy of the old version.
Updates to the Gmail app for iOS [Official Gmail Blog]