In Puerto Vallarta, Blue Chairs is a section of the gay beach. There is also Green Chairs (once known as Loony Toons). The actual gay beach is Playa los Muertos (yes, Beach of the Dead). At the port, ask a taxi for Los Muertos or for Blue Chairs Resort. Both will get you to the same place.
You'll have a great time in PV. Very gay friendly.
Michael (and Mark)