I just got Chromium OS running on a VirtualBox on a Mac OS X Snow Leopard (10.6.7).

I downloaded Ubuntu Linux 10.4 64-bit and got it running on the VirtualBox. I had to allocate a 50 GB disk for this virtual machine–20-25 GB was insufficient.

Following the instructions for building Chromium OS here, I successfully reached the execution of ./image_to_vm.sh --format=virtualbox. This particular script failed at the very end because it expected VBoxManage to be installed locally (which it wasn’t).

I transferred the 3.22 GB vm_temp_image.bin to the host Mac using SFTP, then ran VBoxManage convertfromraw vm_temp_image.bin vm_temp_image.vdi --format VDI

Then, I created a new VirtualBox VM. For Operating System, I selected “Linux” and for Version, I selected “Ubuntu”. For Base Memory, I selected 1024 MB. For Virtual Hard Disk, I selected the existing hard disk vm_temp_image.vdi I had just generated.

IMPORTANT: I then had to fix the network settings. I selected Adapter 1, Attached to: Bridged Adapter, Name: en0: Ethernet. Under Advanced, I selected Adapter Type: “Intel PRO/1000 MT Desktop (8254OEM).

Ten seconds after clicking Start on the virtual machine, I got the initial setup prompts!