According to the latest print edition of The Wrestling Observer Newsletter, published by Dave Meltzer, UFC 86 will take place on July 5 in Las Vegas. The show will be headlined by Quinton Jackson v. Forrest Griffin for the Light Heavyweight title.
Update [2008-3-4 9:23:30 by Luke Thomas]:: Meltzer might be off a bit, because now there are claims the August UFC will be in Minneapolis and feature three native sons:
HT: Reader "Charles"
Update [2008-3-4 9:53:46 by Luke Thomas]:: Ok, I'm pretty sure the July UFC 86 is different from the August UFC 87. Apologies for the mix-up.