Let me start out by saying that this is potentially dangerous and you can brick your device very easily. Always make backups before you flash. If you don’t know what flashing is, then you should probably stay away.
Don’t take my word for it. Here is what the developer had to say about the Extremely Alpha Code.
WARNING: THIS KERNEL MAY NOT WORK ON YOUR DEVICE, MIGHT DESTROY YOUR DEVICE, MIGHT PUNCH YOUR CHILDREN, I AM NOT RESPONSIBLE FOR ANY DAMAGE CAUSED BY THIS KERNEL, USE AT YOUR OWN RISK
It is not as scary as it may seem though. I have never flashed a thing in my life and was able to overclock my Tab with ease. The only problem was that the kernel was not stable. I was able to remedy this by underclocking it again with SetCPU. That was with v1.0 of the kernel. The latest version, v1.2, has not locked up on me once.
The 200 MHz boost is not as noticeable as I would have thought, but it is still there. It can be seen especially well in the default browser using pinch to zoom or scrolling.
You can try your luck with the overclock right now by visiting XDA-Developers. Let me know about your experiences in the comments.