VirtualBox 4.0.10 released On ubuntu 11.04/10.10

Oracle VM VirtualBox, formerly Sun xVM VirtualBox and innotek VirtualBox, is a family of x86 virtualization products for enterprise and home use.VirtualBox is a general-purpose full virtualizer for x86 hardware, targeted at server, desktop and embedded use.

What is new in virtualbox 4.0.10
VirtualBox 4.0.10 (released 2011-06-27)
This is a maintenance release. The following items were fixed and/or added:
GUI: fixed disappearing settings widgets on KDE hosts (bug #6809)
Storage: fixed hang under rare circumstances with flat VMDK images
Storage: a saved VM could not be restored under certain circumstances after the host kernel was updated (bug #8983)
Storage: refuse to create a medium with an invalid variant (for example Split2G with VDI; bug #7227)
Snapshots: none of the hard disk attachments must be attached to another VM in normal mode when creating a snapshot
USB: fixed occasional VM hangs with SMP guests (bug #4580)
USB: proper device detection on RHEL/OEL/CentOS 5 guests (partial fix for bug #8978)
ACPI: force the ACPI timer to return monotonic values for improve behavior with SMP Linux guests (bug #8511 and others)
RDP: fixed screen corruption under rare circumstances (bug #8977)
rdesktop-vrdp: updated to version 1.7.0
OVF: under rare circumstances some data at the end of a VMDK file was not written during export
Mac OS X hosts: Lion fixes (bug #8903)
Mac OS X hosts: GNOME 3 fix
Linux hosts: fixed VT-x detection on Linux 3.0 hosts (bug #9071)
Linux hosts: fixed Python 2.7 bindings in the universal Linux binaries
Windows hosts: fixed leak of thread and process handles
Windows Additions: fixed bug when determining the extended version of the Guest Additions (4.0.8 regression; bug #8948)
Solaris Additions: fixed installation to 64-bit Solaris 10u9 guests (4.0.8 regression)
Linux Additions: RHEL6.1/OL6.1 compile fix
Linux Additions: fixed a memory leak during VBoxManage guestcontrol execute (bug #9068)
Install virtualbox 4.0.10 on ubuntu 11.04
You need to edit /etc/apt/sources.list

gksudo gedit /etc/apt/sources.list

Add the following line

deb http://download.virtualbox.org/virtualbox/debian natty contrib

For ubuntu 10.10 users add the following line

deb http://download.virtualbox.org/virtualbox/debian maverick contrib non-free

Save and exit the file

wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -

Update source list
sudo apt-get update
Install virtualbox

sudo apt-get install virtualbox-4.0

Note: Ubuntu/Debian users might want to install the dkms package to ensure that the VirtualBox host kernel modules (vboxdrv, vboxnetflt and vboxnetadp) are properly updated if the linux kernel version changes during the next apt-get upgrade. For Debian it is available in Lenny backports and in the normal repository for Squeeze and later. The dkms package can be installed through the Synaptic Package manager or through the following command:

sudo apt-get install dkms

Sourcecode : http://www.ubuntugeek.com