Two Step has posted the CSM's Winter Summit schedule and topics. A variety of topics will be covered, ranging from Nullsec to the UI to the economy, and the CSM has requested player input on them all. Two Step has also posted threads for each topic - keep your input to the appropriate threads! The CSM has lobbied to be allowed to disclose as many summit topics as possible, and CCP refused only on four topics. While I'm sure some would like to whine about "excessive use of the NDA", it is not at all unreasonable for CCP to want to keep something they may have worked on but not yet announced under wraps.
In addition, Hans Jagerblitzen has announced a pre-summit town hall meeting, to be held December 8th. The meeting will be held on Eve University's Mumble server (details to connect are posted in the thread) and moderated by Hans and Two Step, as well as EVE Radio's DJ Wiggles. Details to connect to the server can be found here, though regular registration and authentication will not be required during the summit. Alternatively, if you just want to tune in and listen, EVE Radio will be streaming the discussion live.
If you've got a topic you'd like to bring to the CSM's attention for the summit, I encourage you to do so through either channel!