There are a few things:
LIVE Music
LIVE Music will be Microsoft's answer to Google Music. Upload your music library, but in addition, buy new music and stream music to various devices including your Xbox 360. LIVE Music will replace the Zune music service, providing the same service and library of music, but expanding on those services.
Skype for Xbox LIVE
Kinect Video Chat on steroids. Skype for Xbox LIVE will bring video conferencing to the living room unlike anything to date. Skype for Xbox LIVE will expand on the features of and replace Kinect Chat. Providing users the ability to chat with multiple people at once. However, with a paid subscription to Skype, you'll be able have people call you on your Xbox.
Xbox LIVE Silver
Microsoft will introduce a new tier, offering LIVE Free, LIVE Silver, and LIVE Gold. Free will offer the same basic services it currently does, Silver will expand on Free by offering users access to the expanding library of entertainment and communication services available to the Xbox 360. Gold will include all of the features available in Free and SIlver, but offer the addition of gaming services like beacons, cloud storage of profiles, and online gaming.
