I just got done with installing Ubuntu in VMWare. Installer asked me for a username and password which I can now use to log in and out. Installer never asked me for root password. So, what is the root password, and how can I change it?
TIA

There is no root password in Ubuntu. Actually, there is not root account at all in Ubuntu. Use the "sudo" command to do admin tasks, for example:

You will be asked for the password. The password is the same you used to create your user when installing Ubuntu.

You can add a root account to Ubuntu if you dislike the sudo method (which I personally think is great). Just take a look at the Ubuntu guide (which is also worthy bookmarking) about how to enable the root account:

http://ubuntuguide.org/wiki/Ubuntu:Gutsy

use sudo..

sudo <command>

dats it ..

njoy

Maybe I wasn't clear enough in my previous post was I?

The root account is there but its locked so no logins as root are allowed by default.

sudo passwd?

Yup, root account is there, but it's password field in shadow contains exclamation mark which makes the account unusable (! is not accepted, so it can be used to freeze the password, and therefore the account). To start using root account, simply set a password for it with
as suggested by billymayday.

Note that configuring sudo well and using it is more secure than logging in as root all the time. Having root account "frozen" is a step towards better security. Consider learning how to configure and use sudo, it's really not that bad - vice versa. Also your accidental "I shredded my root directory recursively!" situations might get more rare, because typing 'sudo' in front of a command is more difficult to do by accident than just launch a command and not remember that you were actually logged in as root and did a small typing error (maybe you wanted to shred the two files inside the current working directory, but forgot to put a dot in ./ and therefore shredded your root directory - this wouldn't happen, of course, if you didn't have privileges to do that - if you didn't type 'sudo' in front of the command).

Security and secure system is one thing, a secure user and secure habits are another.

I think the OP specifically needs the root password for VMware installation - nothing to do with general maintenance/running.