If your system will not detect new upgrades to ubuntu 10.10, you should edit a file in /etc/update-manager/release-upgrades. follow these steps....

1. open the file "release-upgrades" in  /etc/update-manager/
 with a suitable editor like gedit,vi or something else... in my case im using gedit

then you will see a line like 




you must change it to 


2. then save changes..

  never  - Never check for a new release.

  normal - Check to see if a new release is available.  If more than one new release is found, the release upgrader will attempt to upgrade to the release that immediately succeeds the currently-running release.

  lts    - Check to see if a new LTS release is available.  The upgrader will attempt to upgrade to the first LTS release available after the currently-running one.  Note that this option should not be used if the currently-running release is not itself an LTS release, since in that case the upgrader won't be able to determine if a newer release is available.

3. Now try to upgrade 

3.1. with the terminal 
give command : 

    sudo do-release-upgrade

then your system will check for the upgrades and will ask to do upgrade..

3.2 with GUI open update-manager... you will see a message like " New Ubuntu release '10.10' is available" click on the upgrade button to upgrade...