Change FROM Email Address?

I am running Wordpress 3.2 with Multisite enabled.

When someone submits a comment on a client website, the client receives an email for them to moderate the comment. The email is from: "WordPress wordpress@theirdomain.com"

How can I customize the "From" Email address?

I found this plugin called WP Better Emails. http://wordpress.org/extend/plugins/wp-better-emails/
This is overkill - I don't want custom HTML email template, only to change the from email address.

What are you guys using to customize the "from" email address?