A recent console update allows you to use the PlayStation 4's DualShock 4 controller wirelessly with the PS3.
World Cup Team Rankings: Top 4 Remaining National Teams According To FIFA 14
The change was first pointed on Reddit, and requires you to follow a few steps. The controller will function as if it's plugged in to the system and will function as a generic controller (no rumble or motion controls), but can even be used to power on the system.
The addition came through a recent PS3 update, but was not something Sony went through any special effort to point out. Prior to the update, only the use of a micro USB cable would allow you to use the DS4 on the last generation system.
Check Out The Android TV Controller From Google I/O
Eurogamer has helpfully listed the steps needed to make the DS4 work on PS3, which are not too difficult or time-intensive. You'll need to download the update, of course, and the plug the controller in to the PS3.
Following that, you'll need to register your DS4 as a Bluetooth device with the system, which is done by going to the 'Manage Bluetooth Devices' option in the 'Accessory Settings' menu. Scan for a Bluetooth device, unplug the DS4 from the console, and then hold down the PS and Share buttons. Once it finds the DS4, plug it back in and select 'Wireless Controller'--it should work after that if you've done it correctly!
It might not be a fully functional controller (whether the loss of some features is worth being able to use the superior device is up to you), but it's a nice addition that will hopefully lead to full PS3 support.