I have Ubuntu 10.10 and after few updates the boot menu lists many kernel versions. How do I remove older versions? 
grub shows multiple kernel versions on startup
ubuntu;kernel;grub
Check for currently-installed kernels:$ dpkg --get-selections | grep linux-imagelinux-image-2.6.38-2-686-bigmem         installlinux-image-2.6.32-5-686                installCheck what current kernel you are running:$ uname --allLinux debian 2.6.38-2-686-bigmem #1 SMP Thu Apr 7 06:05:53 UTC 2011 i686 GNU/LinuxRemove the kernel(s) you are displeased with, generally keeping the latest (and greatest).$ sudo apt-get remove linux-image-2.6.32-5-686I think it's a good idea to keep at least two different versions though. However, I think this advice used to be more useful some time ago, because it seems the kernel gets more and more stable (I experience far less trouble than I used to), but maybe I'm lucky.