Download Pre-configured and Pre-built open source OS VirtualBox images
If you want to try out open source OS such as Ubuntu, Fedora, OpenSUSE, CentOS, FreeBSD, OpenSolaris, without going through installation from the beginning, you can download pre-built VirtualBox (VM) images.

smallwei 8:34 am on November 20, 2009
Here is the list of all the images as of Nov, 2009. The link to the downloaded page is at the end.
GNU/Linux (GNU userland tools running on top of the Linux kernel)
* Archlinux (website).
* CentOS (website): the installation is done from the DVD, with default parameters set
* Damn Small Linux (website): the installation is done from the CD, with default parameters set.
* Debian (website): the installation has been done from the netinstall ISO image for the x86 architecture.
* DeLi Linux (website).
* Dreamlinux (website): the installation has been done from the CD, with default parameters set.
* Fedora (website).
* Fluxbuntu (website): the installation is done from the CD, with default parameters set.
* Gentoo (website): the installation is done from the ISO image, then customized .
* gNewSense (website): the installation is done from the CD, with default parameters set.
* gOS (website).
* Kubuntu (website): the installation is done from the CD, with default parameters set.
* LinuxMint (website): the installation is done from the CD, with default parameter set.
* Mandriva (website): the installation is done from the CD, with default parameters set.
* Moblin 2 (website): the installation is done from the .img/.iso file provided by the project.
* moonOS (website).
* OpenSUSE (website).
* PCLinuxOS (website).
* Puppy Linux (website).
* Sidux (website).
* Slackware (website): the installation has been done from the first CD, selecting the bare minimum disk sets.
* SliTaz (website)
* Tiny Core Linux (website)
* TinyMe (website)
* Ubuntu (website): the installation is done from the CD, with default parameters set.
* Ubuntu Studio (website): the installation is done from the CD, with default parameters set
* Xubuntu (website): the installation is done from the CD, with default parameters set.
* VectorLinux (website):the installation is done from the CD, with default parameters set.
* Zenwalk (website): the installation is done from the Standard Edition CD, with default parameters set.
GNU/OpenSolaris (GNU userland tools running on top of the OpenSolaris kernel)
* OpenSolaris (website).
* Nexenta (website): the installation is done from the CD.
* MILAX (website): the installation has been done from the official ISO image.
BSD
* FreeBSD (website):the installation is done from the bootonly iso
Other
* AROS (website): the installation has been done from the nightly build ISO image.
* FreeDOS (website): the installation has been done from the official ISO image.
* Haiku (website): the image has been done from the nightly build HDD raw image.
* MINIX (website): the installation has been done from the official ISO image (MINIX 3).
* ReactOS (website): the installation has been done from the official ISO image.
* SYLLABLE (website): the installation has been done from the official ISO image.
* Android-x86 (website): the istallation has been done from the daily ISO image
Download: http://virtualbox.wordpress.com/images/