Available tomorrow, here are some of the new features courtesy of Gamerscoreblog that will be available using the new Windows Messenger options: 

• Chat via instant messenger with up to 20 contacts in a single conversation, and have up to six different conversations at the same time with people on PCs, mobile phones and other Xbox 360 consoles.
• Instant message while playing games, listening to music or watching movies or TV shows downloaded from Xbox LIVE Marketplace.
• View at a glance if friends on Windows Live Messenger have gamertags and add them to a unified friends list.
• Utilize the virtual keyboard on the Xbox 360 to text chat or connect a USB keyboard to the console.  Launching later this summer, the Xbox 360 text-input device accessory will connect directly to the controller to support instant messaging.

Here are some other new details that will also be available with the new spring update:

• On-screen pop-ups that immediately display the name and gamerscore value of a just accomplished Achievement, allowing gamers to see their progress without leaving or pausing the game.
• An even safer way to communicate through Xbox LIVE with enhanced family settings that enable different default settings for video chat and voice chat.
• A new, standalone Xbox LIVE Marketplace blade houses all Xbox LIVE Marketplace content in one easy to navigate space.
• Xbox LIVE Arcade enhancements that showcase what games friends are playing directly from the friends list. Boasting about high scores, comparing progress and checking out leaderboards are all easier now as well.
• Faster access to free, trial version of Xbox LIVE Arcade games through an improved Auto Downloads feature.
• The ability to fast-forward, pause and rewind video as it is being downloaded on Xbox LIVE Marketplace.
• Owners can now set their consoles to turn off after downloading content from Xbox LIVE Marketplace to help save energy, and download speeds have been increased.

The update is free as always and will be available tomorrow afternoon.