Virtualbox, is a virtualization software, from innotek. Which is their own virtualizer, so it is not based on xen or qemu. And have support for HVM, which I read from some forum, it is better leave as is, than enable hardware support.
What cool is there is an open source edition(or the OSE on their website), and free in price version. The difference is the OSE version don’t have the USB emulation, built in rdp, and using iscsi as a virtual disk, Since I got some USB device I opt for the OSE version.
The OSE version is in ubuntu repository, and probably other distro repository too.
What is really-really cool is that, they provided package for different linux, which is rare among proprietary software company, and repository for ubuntu too. Which is way cool. Since I am lazy. You can get it here.
For those who used other virtualization software before, you will noticed that, it provide most features that a virtual machine have, like sound support, able to use usb device, probably not build in rdp support. So using it is not hard, except, you need to get use to the interface a little.
Another cool thing is, there is seamless windows integration which means that, you maybe run a program on virtual machine, but you see it on your desktop. And you can share the clipboard too. This is a totally cool feature.
You also can setup a shared folder that is shared between virtual machine and host machine. On vmware, it means that you need to have a samba server to do so. But on virtualbox, you can do that without need a samba. To windows, or linux, it is a windows shared folder, but you don’t need to install samba.
Other thing, include, sharing clipboard, HVM support(but it seems experimental, probably not yet, slower than just running virtualbox alone), able to support the host sound server, which it can use pulse audio,
I think this is quite a nice product, like most commercial product, easy to use. Unlike commercial product it is free, in price, and for certain part in rights too. And unlike more well known product, it have features unique enough(aka seamless integration), to standout on its own. So far it run quite fast, but then I have a gig of ram. To run a virtual machine make sure you have more RAM, anything above 512 Meg is nice. But 1 gig is good enough, 2 gig is much nicer, a gig for linux, a gig for windows virtual machine