It's the easiest upgrade you can imagine on the inside of a computer. Take a small flat bladed screw driver and carefully pry the chip out of its socket. Don't lift one side of the chip out of its socket all at once or you might break some of the pins, but alternate sides and lift it bit by bit. The code word is 'careful'.
As an alternative to the screwdriver approach, you might try a cheap IC extractor. To pull the ROM I had bend the extractor out a bit before attaching it as they are normally meant for smaller chips. You still want to carefully rock the chip back and forth out of the socket. But I've found this approach a bit easier than the screwdriver method.
My extractor looks like this
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_16838_-1
