I don't understand why you want to get rid of the Tab Bar. It's a standard iOS control that allows users to see all the possible task-oriented views of the application:
A tab bar gives people the ability to switch between different subtasks, views, or modes.
If you replace it with a slide-out sidebar like Facebook does, you'll make the users apply more effort to explore the options, which may turn off some of them since they won't see what they want right away.
Moreover, Facebook's decision not to use the Tab Bar is quite obvious: they have too many items to fit into it comfortably. Since you have just 3, you shouldn't have a problem with the real-estate in the Tab Bar.
Nonetheless, if you wish to sacrifice discoverability of your app's functions, you can do something like what Plume does on Android: the title bar has an icon indicating it's a drop-down and tapping it opens the list of other views:
For the record: it's a crop of the official screenshot - I don't even know who @Shadylife is.