if you are fans of VirtualBox like me, the new version of VirtualBox; VirtualBox version 3.0.4 has been released per 4 August 2009.  Lets download the VirtualBox binaries here:

http://www.virtualbox.org/wiki/Downloads

VirtualBox is an X86 virtualization software developen by Sun, distributed under two license, PUEL (Personal Use and Evaluation License) and GNU/GPL license.

Wikipedia said, VirtualBox is an x86 virtualization software package, originally created by German software company innotek, now developed by Sun Microsystems as part of its Sun xVM virtualization platform. It is installed on an existing host operating system; within this application, additional operating systems, each known as a Guest OS, can be loaded and run, each with its own virtual environment.

Supported host operating systems include Linux, Mac OS X, OS/2 Warp, Windows XP, Windows Vista, and Solaris; there is also experimental port to FreeBSD.^[1] Supported guest operating systems include various versions of DragonFlyBSD, FreeBSD, Linux, OpenBSD, OS/2 Warp, Windows, Solaris, Haiku, Syllable, ReactOS and SkyOS.^[2] The latest version also supports Windows 7 beta and release candidate 1.

VirtualBox 3.0.4  comes with series of bug fix and improvements. The following items were fixed and/or added:

• VMM: 64 bits guest stability fixes (AMD-V only; bugs #3923 & #3666)
• VMM: SMP stability fixes (AMD-V only)
• VMM: SMP performance improvement (esp. for Solaris guests)
• VMM: eliminated several bugs which could lead to a host reboot
• VMM: fixed OS/2 ACP2 boot floppy hang (VT-x only)
• VMM: small performance improvement for OpenSolaris guests (AMD-V only)
• VMM: fixed CentOS/Xen reboot (software virtualization only; bug #4509)
• SATA: fixed hangs / BSOD during Windows XP installation (bug #4342)
• SATA: mark the ports as non hotpluggable (bug #3920)
• 3D support: fix deadlocks and context/window tracking for multithreaded applications (bug #3922)
• 3D support: fix memory leaks when terminating OpenGL guest applications
• 3D support: fix crash in Call of Duty
• NAT: using two or more NAT adapters in one VM was broken (3.0.0 regression)
• NAT: fixed network communication corruptions (bugs #4499, #4540, #4591, #4604)
• NAT: fixed passive ftp access to host server (bug #4427)
• iSCSI: fixed cloning to/from iSCSI disks
• GUI: fixed path separator handling for the OVF export on Windows (bug #4354)
• GUI: the mini toolbar was only shown on the first host display (bug #4654)
• GUI: added a VM option to display the mini toolbar on top
• GUI: don’t crash when adding plus configuring host-only network interfaces
• Shared Folders: fixed selection of a drive root directory as a shared folder host path in VirtualBox (Windows host only)
• USB: fixed a bug that may have rendered USB devicefilter settings inactive (3.0.2 regression, bug #4668)
• Guest Additions: report the Guest Additions version to the guest properties (bug #3415)
• Mac OS X hosts: fix creation of VMDK files giving raw partition access (bug #1461)
• Mac OS X hosts: improved support for Snow Leopard
• Linux hosts: fixed problems leading to wrong colors or transparency in host windows with some graphics drivers (bug #3095)
• Linux hosts: hardware detection fallbacks if the hal service fails to find any DVD drives.
• Linux and Solaris hosts: Work around color handling problems in Qt (bug #4353)
• Solaris hosts: fixed memory leaks in host-only networking
• Solaris Installer: fixed incorrect netmask for Host-only interface (bug #4590)
• Solaris Installer: added package dependency for Python and Python-devel (bug #4570)
• X11 guests: prevent windows from being skipped in seamless mode KDE guests (bugs #1681 and #3574)
• X11 guests: fixed screen corruption in X11 guests when large amounts of video RAM were allocated (bug #4430)
• X11 guests: some fixes when switching between host and guest-drawn mouse pointers.
• X11 guests: fixed an issue which caused seamless mode to stop working as it should (the main issue listed in bug #2238).

If you are new to VirtualBox, read this and this article. and also here the user and technical guide.