Since a lot of people want to upgrade to Ubuntu 11.04 Natty Narwhal already, I though you'd like to see a video (well actually 2) on how to upgrade to Ubuntu 11.04. Remember that starting with Ubuntu 11.04, you can upgrade using the Live CD too.
1. Upgrade to Ubuntu 11.04 Natty Narwhal via Update Manager (requires an Internet connection)
Upgrading to Ubuntu 11.04 via the Update Manager requires an Internet connection. All you have to do is press ALT + F2 and type:
update-manager -d
The update manager should then notify you that a new Ubuntu release "11.04" is available - click "Upgrade" and follow the on-screen instructions.
Here's a video I've created (in VirtualBox - I've only recorded the important parts) to show you how the upgrade process from Ubuntu 10.10 to Ubuntu 11.04 works, for those who've never upgraded before:
2. Upgrade to Ubuntu 11.04 Natty Narwhal Using A Live CD (doesn't require an Internet connection)
You can upgrade to Ubuntu 11.04 even if you don't have an Internet connection (you can use this with or without an Internet connection). All you need is an Ubuntu 11.04 Natty Narwhal CD or bootable USB drive (you can create a bootable Ubuntu USB using the built-in Ubuntu Startup Disk Creator in Ubuntu or Unetbootin which works in both Ubuntu and Windows and so on). Once you boot into the Live CD, select to upgrade Ubuntu 10.10 to Ubuntu 11.04.
What's weird is that the Live CD will ask you to enter your username and password again which seems pointless since you're upgrading so just to make sure, use the same username and password that you had in Ubuntu 10.10.
Here's a video (trimmed to the important parts) showing the Ubuntu 11.04 upgrade process using a Live CD:
For both videos: please note that when you upgrade, if your hardware supports it you'll see Unity and not the classic Ubuntu Desktop. In my videos, the classic Ubuntu desktop shows up because I'm using VirtualBox and I didn't install the Guest Additions (which by the way are broken for about a week or two).