You could post a message today at 12:00PM US/Central that the tournament is starting exactly this time tomorrow. Everybody would just compare this to the time displayed in the heading of you post in order to find out what the time difference is.
Streamed Live 1v1 Tournament #3: 9/21/2012 17:13:10
I'd like to sign up for this match, I may not be the best player, but I try, and I'm doing OKish on the 1v1s I've played so far (loads of silly mistakes :(
Streamed Live 1v1 Tournament #3: 9/21/2012 19:56:39