Back in May, BlackBerry had announced plans to release its popular BBM messaging service to other platforms such as the iOS and Android later this summer.

While BlackBerry is yet to announce the release date, we got some hints that the company is gearing up for the launch, after it started sending out invites to a small number of users on BlackBerry Beta Zone to test the app earlier in the month.

While the wait for the app continues, the user guides for BBM for iOS and Android has just leaked online.  We’re not making this up, BlackBerry has actually created a comprehensive user guide for the app, which we doubt anyone will read when the app is released.

The user guide doesn’t include screenshots, but as Cult of Android points out, it does reveal the features that won’t be available at the time of the launch.

Features like BBM Groups, profiles, emoticons, and contact blocking are all available, but you won’t find BBM screen sharing, video calling, or the new BBM Channels feature.

If you already have a BlackBerry ID, getting started with BBM on Android and iOS will take you just a few minutes; simply sign in and any saved BBM data associated with your account — such as your contacts list — will appear.

Here’s a screenshot of the BBM app for Android that had leaked earlier in the month. We expect the iPhone app to offer a similar user interface.

When BlackBerry launches the BBM app for iOS, BlackBerry will join Google, Microsoft and Nokia in making apps for competing platforms, whereas Apple has adopted an iOS-only policy for its apps.

It remains to be seen if BBM app will be popular on iOS, especially with hugely popular cross-platform messaging apps like Whatsapp.