From personal experience; collecting email addresses at this stage would be the best way to go. Ask people a little bit about themselves as nearly 80% of people who say they're interested will flake out closer to the date.
Think I'll be back in Edinburgh by the 6th Nov, but if anyone feels like meeting up before end Oct, give me a shout (I think details are in my profile).
Would be nice to meet other any other hn users over here.