Facebook for Android v1.5, the latest version of the Facebook mobile app for Google’s platform, is now available in the Android Marketplace. It adds Chat and push notifications, two features sorely lacking from previous releases and heavily requested by users. We’ll go over the new features now, and will update with screenshots and a discussion of usability soon.

This update closely follows version 1.4 which was released December 3rd, and gave users access to Facebook Places and Groups. Android phones also recently received single sign-on, which reduces login friction for third-party Facebook integrated apps. Facebook for Android now only lacks a few minor features available on the iPhone, namely photo tagging, Facebook Deals, and advanced Places functionality including photo check-ins and the ability to add tags of friends to an existing check-in.

The added Chat functionality eliminates the need to use a third-party, Facebook Chat-compatible mobile app such as Go!Chat. Chat for Android runs properly in the background, which the announcement says allows users to”receive chat messages while using other applications”. Chat can thereby simulate SMS, which can help users save money.

The new push notifications will help users stay aware of activity on their Facebook accounts in real time, reducing the need to constantly check the app when awaiting a wall post or message. It will also prompt less engaged users to occasionally open Facebook for Android, which could lead to a growth in daily active users.

Comments on the announcement of the app are overwhelmingly positive and appreciative of the progress the app has made — a strong shift from the comment reels of previous release announcements which were filled with complaints about the lack of Chat and push notifications. If the Facebook for Android team can keep up this pace of updates, the app may soon rival Facebook for iPhone for the title of most advanced Facebook mobile app. That would be a big shift which could drive Facebook power users to the Google platform — something that could aid the launch of Google’s upcoming social product which may be more mobile focused.