Standard disk image format?

[50words]

Is there a standard disk image format that I can use on most virtualization apps? Or at least one that is accepted across two or three?

At the moment, I am using Virtualbox, but I would like to try the others without reinstalling Windows XP in each one.

For the future, I just like to be able to skip around between different software. I do this with my e-mail, calendars, etc., and I would like to do it with my Windows XP disk image, as well.

[luisromangz]

VirtualBox works with its own hard disk image format (obviously) and VMWare's. There is no standard though, but maybe VMware's file format is the best choice.

[50words]

That would be the vdmk extension, right?