Good luck mate.
By far, the hardest part is getting the old chip out without damaging the board.
Unless you have a very good desoldering station, I find it's much esier to cut the old chip out with a dremel and VERY steady hand. Cut close to the chip body and you can then easily desolder and remove the pins one by one.
Obviously you have to go slowly and carefully when using any tool around your precious boards.
