Can you use our tool http://EventGel.com/ to coordinate this and tell us what you think? This is our new startup. Since we are aiming to be useful to exactly the thing that you are planning, it will be great if you can tell us how practical our tool is and how we can make it work better for you. [our earlier HN post : http://news.ycombinator.com/item?id=883731 ]
I just wanted to add that we're working on the design right now, so the look of the page is going to change in the next day or two.
I'm not sure if anyone is still reading this thread; but if you are we recently launched our redesign of eventgel. Hopefully it is a little easier to use now.