The new Facebook app seem to have done away with the grid-icon layout, with a more interesting custom navigation layout where the bottom-most view shows all the options (like Profile, News Feed, Messages etc for Facebook) and clicking on one of them brings another view sliding over the top. You can press the 3-lines button to then expose the bottom-view again, but the current view is partially visible. The Path app also recently updated to match this scheme.
What's the best way to recreate this? I've searched for any open-source options but haven't found them. Three20 doesn't seem to support this either.
if anyone's wondering which one to choose among JTReveal and DDMenu, I'd suggest DDMenucontroller over JTRevealSidebar (haven't used the other options listed by @Yosi). Its a lot simpler, lighter and works exactly the way the Path app works (and it is easier to modify to suit your requirements). Havent seen the issue of black background mentioned by @Henning
This project (not mentioned above) looks like the most mature and polished to me: https://github.com/gotosleep/JASidePanels
Also, seems to still be active.
Edit: I have since transitioned to: https://github.com/mutualmobile/MMDrawerController which IMO is an almost perfect implementation.
Try These from Cocoa Controls:
JTRevealSidebar http://cocoacontrols.com/platforms/ios/controls/jtrevealsidebar
clcascade http://cocoacontrols.com/platforms/ios/controls/clcascade
StackScrollView http://cocoacontrols.com/platforms/ios/controls/stackscrollview
Many more on the same site like: http://cocoacontrols.com/platforms/ios/controls/mfslidingnavigationcontroller http://cocoacontrols.com/platforms/ios/controls/psstackedview
Another option that I wrote: ECSlidingViewController
It has support for orientation changes like Facebook and sliding to the left like Path.
Video demo: http://vimeo.com/35959384
Code: https://github.com/edgecase/ECSlidingViewController
Here is one thats very easy to implement and use with storyboards. It has control for shrinking, show hide animations, and direction.
https://github.com/HelloMihai/HMSideDrawerDirectional
My project FRLayeredNavigationController on GitHub goes in about the same direction.
(The spacing between the layers is easily configurable and it supports rotation of course).
Have a look at the demo videos/screenshots: