iTunes Match does streaming your music library to your iOS device. Earlier posts of mine suggested otherwise. A good samaritan on Twitter pointed me to this MacTrast link. I'm gonna make you go over and check it out. They've got a youtube video showing it working.
This information is also confirmed on Macrumors.
It all comes down to semantics I guess as far as how Apple wants to definite "streaming". It's like wireless carrier's definition of "unlimited" or Google's definition of "open"