A quicker way to access your update manager and check latest available updates for your system through your Ubuntu Unity top Panel using Update Manager indicator.
You simply can navigate through a drop down menu for available packages update, refresh your currently active repositories for new updates, Also you can check update manager indicator preferences for changing time interval between checking for updates, disabling update manager auto popup, showing notifications, showing passive icon.
Install update manager indicator On Ubuntu 11.04 Natty Narwhal and Ubuntu 11.10 Oneiric Ocelot
Run terminal to add the repository and install the package
sudo apt-get update
sudo apt-get install indicator updatemanager
Search in your applications menu update manager indicator and run it.
Thanks to Jonas Frei and webupd8 PPA.
sudo apt-add-repository ppa nilarimogard/webupd8 needs to be changed to: sudo apt-add-repository ppa:nilarimogard/webupd8
Also last line should be sudo apt-get install indicator-updatemanager
Sorry about typos. Post updated.