In an effort to murder MySpace in cold blood create more of a rapport between Facebook Pages and third-party websites, Facebook has launched the “fan box.”

Aside from sounding vaguely obscene, the Fan Box is a widget for companies, bands and brands to embed on a site to promote Facebook Pages. Adding the function involves merely including a snippet of Javascript code on your site. Operating somewhat like that handy little “share” button, it lets site visitors fan your Facebook Page with one click. From Inside Facebook:

“Users can view the most recent posts from the Page, see a list of other fans (including their friends), and, most importantly, become a fan without leaving the site,” Facebook Product Manager Mark Kinsey says. “Additionally, if a user visits the site and isn’t logged in to Facebook, the user can log in and become a fan directly inline as well.”

In other words, users can authenticate themselves to the widget using Facebook Connect in order to become Facebook fans without leaving your page. Later, when logging into Facebook, fans will see your updates in their stream just as they would any other Page they had become a fan of inside Facebook.com.”

The new feature is doubtlessly of huge importance to musicians and companies who wish to leverage their social media following more effectively. But in the whole debate over whether Facebook has killed MySpace, the one redeeming value constantly cited to keep MySpace alive is “the music.” The last big story about MySpace was regarding massive layoffs. Will this function put the final nail in MySpace’s coffin?

The change, expected to be put into place next week, will turn users’ news feeds into streaming updates on their Facebook friends. The homepage will also get somewhat of a makeover, with added options for feed filtering.

Facebook is also preparing to revamp and beef up its advertiser pages, also known as “Facebook pages.” The changes include a more user profile-like appearance for the ad pages. The pages will gain a greater presence in users’ Facebook news feeds, including the ability to send status updates as regular users do.

The old Facebook Pages design

Additionally, the branded profiles will begin featuring tabs, with different kinds of content in different sections (i.e. external applications will fall under a “boxes” tab instead of residing on the primary page). Companies will then be able to configure which tab they want to serve as the main landing page for any given time period.