Here's something to start with for hiding the sidebar:

#main {
	background:none;
}

#content {
	width: 940px;
}

footer.entry-meta {
	width: 895px;
}

The really tricky part is changing the background and sidebar background colors since they’re built in using images.

Here’s an awesome post from Sheri for an idea of what it would take:

http://en.forums.wordpress.com/topic/change-background-colours-in-piano-black-theme?replies=12#post-850999

I'd like to remove the sidebar from my Piano Black blog, but know nothing about CSS. I do have the upgrade, and the WordPress staff sent me here to the forums to find out how to do it.

It's the only change I want to make, but I don't know where to start. Any help would be appreciated!

Scott