After using VirtralBox, I was starting to find the widescreen solution. Because of the original VGA driver in XP VM doesn’t support 1280×800 or 1440×900.
I spend a few time to find out the correct step in Internet. I record here to avoid I forget.

Step:
1. Start the VM (ex. run XP)
2. Open the terminal and type:

VBoxManage controlvm “Windows XP” setvideomodehint “1440″ “900″ “32″

Windows XP is the name of VM
This command is change the resolution to 1440×900 32bit color