I am using a Macbook Pro 2.53 Core 2 Duo with OS X 10.6.4 and used Windows XP for the installation. I have legal copies of XP, Vista, and Windows 7 and chose XP since I only use 2 or 3 programs in Windows and do everything else on the Mac and XP uses fewer resources than either of the other newer versions.
The general steps for installing are below with the usual disclaimers about making sure the settings are correct for your system and this forum or myself take no responsibility if any of these steps have a negative impact on your system, etc.
1. Download the disk image for VirtualBox here: http://www.virtualbox.org/wiki/Downloads.
2. Download the VirtualBox User Guide, and refer to it for questions. I found the answers I needed during the installation and set up.
3. Install VirtualBox.
4. Open VirtualBox (VB), click on the "New" icon and follow the wizard to set up your new virtual machine. I used all the default settings, except set the memory to be used at 1024. (Minimum requirement for XP is only 64, 128 recommended and if possible you should probably set 512 if you can. I may move my memory setting lower if the performance on the Macbook degrades.)
VB will then create the virtual machine based on the settings you provide.
5. Insert your Windows installation CD in the drive.
6. Double-click the entry for the virtual machine you created to "start" the machine and then follow the steps to complete the windows installation. There are several information messages given by VB during this process. Read them carefully so you understand what is going on.
7. Once windows is installed, perform all needed updates to makes sure your windows installation is current.
8. Install the VB Guest Additions, with the virtual machine running, choose Devices from the VM menu and choose Install Guest Additions. This will require reboot of the virtual machine.
9. With the virtual machine running, choose Devices->Shared Folders... and choose which Mac folders you want to share. (I just shared my Documents folder.) Then shut down windows and restart the virtual machine. If you don't see your shared folders, refer to Chapter 4, Section 3 in the VB User Guide and follow the instructions to see your shared folders.
Once I reached this point, I was able to install The HTML Editor and the other programs I use in Windows and all worked great.
Remember, you need to install virus protection in your virtual machine, I use Microsoft Security Essentials since it has worked very well and is also, you guessed it, free!
Happy Windows CoffeeCup HTML Editor'ing on your Mac.