BootCamp 5 + Windows 8 troubles (unsupported hardware?)
Note that the 13" MacBook Pro, mid-2010 is NOT supported.  If you have a 15" or 17" model, then you should be able to update to OS 10.8.3 (DO NOT do this if you have a 13" model) and get Boot Camp 5.

Download link for 10.8.3 (only if you have a supported Mac): http://support.apple.com/kb/DL1640

If you have a 13" model and you've updated to 10.8.3, you may be out-of-luck unless you downgrade back to 10.8.2.

As of 10.8.3, they've added checks to the OS (and, it seems, bootloader) to check for a Windows 8 disc.

If your device is unsupported (see link [2] at the bottom), BootCamp Assistant will refuse to help you, stating instead that "Windows 8 is not supported on this Mac."

You can still manually resize the HFS+ partition (the one that Mac OS X is installed on) via the Disk Utility.

However, from my experience, trying to boot to the "UEFI" Windows 8 disc manually (by holding Alt/Option when turning your Mac on) just results in it loading into the Mac OS. (Preventing a Windows 8 install.)

I downgraded to 10.8.2 and was once again able to install Windows 8.

As far as the BootCamp drivers in Windows 8:


Regardless of whether you use the BootCamp 4 drivers (for Windows 7)
or manage to obtain the BootCamp 5 drivers, you will need to
navigate to the "\BootCamp\Drivers\Apple" folder in an Explorer
window in Desktop mode.
Next, go to File -> Command Prompt -> Open command prompt as
administrator.
From there, type ".\BootCamp.msi" to launch the installer.


This should get around any "unsupported machine" issues.

Final note if you have NVIDIA graphics:
Boot Camp 4's NVIDIA drivers are NOT COMPATIBLE with Windows 8.
These will likely result in your screen going black until you restart.  At which point, you should go to NVIDIA.com and download the latest drivers.
You can, potentially, stop these from being installed by using the Task Manager and choosing "End Task" on any NVIDIA installation during the Boot Camp 4 install.

Hopefully, this will help you get around Apple's attempt to force you to buy a new computer.

Official Apple Info:
[1] Apple's Boot Camp \ Windows 8 FAQ: support.apple.com/kb/HT5628
[2] List of which Macs support Boot Camp 5: http://support.apple.com/kb/HT5634