I've checked around and still can't find out. I have my tickets too, I'm a little bummed though because it's Matt, Al, and Jason Roeder from Neurosis on drums - not the original Sleep line up - it's still going to kick ass though.
I did a poster for Om in December and managed to squeeze some info about the Sleep posters this summer (after BEGGING to do one myself and being politely rejected). I don't think i have ever been so psyched to see a poster before.
It was a miracle I got into this show, I missed out on ticket sales and a friend of a friend had an extra. I found out an hour before they went on stage. They played everything so slow... absolutely perfect.