sources.list for upgrade to 11.04

[Lenny]

Hi,
As in my last message, I am still working on upgrading my Ubuntu 10.10 to 
11.04.
I did the command:
sudo do-release-upgrade
and it had trouble getting the packages from the repositories.
To test things, I did:
sudo apt-get vim
and successfully installed the text editor for editing the sources.list 
file.
There are two lines in the first section, which looks to be for upgrades.
Is there another line I can enter to be sure to find a mirror for the 
upgrade?
All the lines that are not hashed out have "restricted" at the end of the 
line.
Thanks for any help.
Glenn