UPDATED:
Facebook has added several features that should bring more music related activity to the popular social networker and be a boon for artists and labels.
Central to the effort are Facebook Pages which enable bands (or any entity) to build a central location for interaction with fans on Facebook. Those pages can also be leveraged with targeted Social Ads as well as self-service Facebook Ads (the successor to Facebook Flyers) which offers affordable targeted ads priced by clicks or impressions.
In a unique feature sure to upset some privacy advocates, marketers can also track fans by adding code to their own web sites that link to Facebook Beacon. After a Facebook member visits the encoded site, their activity can be shared with other Facebook friends and advertisors leading to targeted ads. For example, a visit to an encoded PinkFloyd.com can land an ad for their box set on your Facebook page.
Here's one early example of a crudely done Facebook band page.
