One cheap and easy way to do this is to drill a small (50 to 100 mils) hole in the center of the pad on the PCB. Solder the pad itself but not so much it puddles. Solder or at least flux the pad on the IC and solder just the corner pins to the PCB.
Put a 60 watt or so solder iron with a small chisel tip into the back of the PCB and into the hole you drilled. This will heat the IC pad and the PCB pad enough to fuse together. Use a gloved finger to press the IC flat as it fuses to the pad. STOP the instant this takes place. Now you can manually solder or use infra-red or a heat gun to solder the remaining pins.
This works well once you have done it a few times. You do loose some heat transfer to the PCB using this trick, but less chance of damage from cooking the IC or PCB if other procedures last too long.