Kernel v3.0 is out there and will be released with Ubuntu 11.10 and yet, there are no kernel updates for Ubuntu 11.04 after Kernel v2.6.38. If you are very eager to install kernel 3.0, then you can build them directly from the source code. Or just use the packages that are used to install Kernel 3.0 on Ubuntu 11.10. Since the latter approach is simple and easy, I will mention step by step instruction to install Kernel v3.0 on your Ubuntu 11.10 Natty Narwhal.
Step 1: Download the debian packages from here.
For 32 bit users -
Step 2: Once you have downloaded all the files, place them into a single folder. Browse to that folder from your terminal and then copy paste the following code into the prompt.
sudo dpkg -i linux-*
The execution will continue to install kernel 3.0 on your Ubuntu 11.04. Just in case kernel 3.0 mess up, do not remove previous versions. You can always choose from the previous versions in the grub.
If you have or happen to install this, then please comment on the power consumption and other pros and cons of kernel 3.0.