I have installed Ubuntu in vmplayer, as the vmplayer does not support Unity of Ubuntu, I want to be able to open the image in virtualbox. How can I do this?
First I assume by vmplayer you mean VMware Player?
You should be able to simply open your VMware disk (.vmdk) in VirtualBox.
n.b. this won't work the other way around, i.e. you can't open VirtualBox disks with VMware Player.