Just a little info on what I experienced using virtualbox 2.1.
I installed virtualbox 2.1 from its website and installed Windows XP in it. I found that the cursor could not be captured and discarded at will, It was a hit and miss problem. Sometimes I could capture it and then when I discarded it I could not recapture it. I was just about to give up and just partition my computer and install Windows XP on the new partition.
I decided to try one more thing and that was to install VBoxGtk.
Once I installed VBoxGtk and accessed Windows XP, SunxVM VirtualBox appears and Windows XP loads and everything works excellent.
Just thought I would share the info in case anyone else had this problem.