In Debian 6, right after my installation. I try to run a command as root, only to find out that my account isn't in the sudoers file. This is from the main user account that is set up under installation.
I have install Debian 6 as a virtual machine under VMware Workstation.
When you install the server and create the original user, you have the option to choose what groups the user should be in. That's where you need to add that user to the group that's allowed to run sudo. For most Unix systems, that group is called wheel, or possibly sudo.
Since you didn't do that from the start, you will need to log in as root, edit the file /etc/groups and add your username to the correct group.
There's some more information about sudo on debian at the Debian wiki.
