Higher screen resolution for VirtualBox?

This worked for me and I am running VirtualBox 4.1.8 and Ubuntu 11.10.

sudo apt-get install virtualbox-guest-utils virtualbox-guest-x11 virtualbox-guest-dkms

Found it on this site under a slightly different question Higher screen resolution in VirtualBox?

I was able to reproduce this issue repeatedly on Windows 7 host with Ubuntu 11.10 guest. Installing ubuntu from an iso image.

This issue happens when the either the Guest Additions are not installed or installed from ubuntu sources.

To fix this install guest additions from the virtual machine's Devices > Insert Guest Additions CD image option and running the autoprompt. If you already have the guest additions installed from a different source it will prompt you about removing the existing one and installing new guest additions, just say 'yes'. This will remove the guest additions if they are already installed from ubuntu sources and build from sources that came with your virtualBox installation.

This should fix the issue.

I just installed Ubuntu 12.04 on VirtualBox 4.1.4, but couldn't get it to work on higher resolution, even after installing and reinstalling the VBOXAdditions. Desperate, I installed the VBOX 4.1.14 and reinstalled many times the VBOXAdditions, but without any success. Finally, the solution that solved the problem, was to increase the video memory (in VBOX setting for Ubuntu) from starting 12 MB, to 48 MB (which still did not enable resolution 1366x768), and than to 128 MB. After restarting Ubuntu everything works perfect, 1366x768 is my default resolution. I hope this will help in your problems. Cheers!