Add lots of solder until it bridges the contacts and the part will come free - small chip components will generally stick to the iron at this point and you just wipe them off. Clean up the pads with solder wick.
This video kind of shows the technique, though he uses a bit less solder and uses the iron itself to bridge.
It is important that all the pads are heated or you risk lifting them. You can sometimes get away with jumping back and forth from side to side, but its easier just to bridge the whole thing for small components. Do not try to force the component to move - minimal pressure. If the solder isn't molten, you will damage the PCB if you apply pressure.
You can remove small ICs this way too, I've even done a 28 pin SOIC. There are special solders made for removing stuff like large QFPs.
One time I had to rework a bunch of LCD boards by replacing 6 tiny little SMD resistors - after a few hours I could remove the whole lot with one quick swipe of the iron. The blob of solder and resistors would follow the iron across the board like a katamari.