The iTunes Match Beta was released last night and for the first time, confirmed that Apple will have streaming as well as the option to download the music. MacRumors has some screenshots and video of the service in action.
Remember, this is a beta, so it is possible streaming could be removed for some reason. When AirPrint was in beta it worked with all types of printers, but by when it was released, it was scaled back to a handful of HP printers.
I personally began using iTunes Match last night and am so far quite impressed. I freed up 14GB from my iPhone and can now listen to all of my music on my MacBook Air without having to worry about my small SSD.