Lpc2000

I've got two (naive) questions..

1. The LPC2106 seems to have two sets of JTAG pins, which can be
selected by using the alternative function pin definition bits.  How
does this work?  Emulation happens during reset, before anything is
programmed.  How does the designed specify which pins to use?  Just
pointing me to the right place in the users manual will be great.

2. I've seen a few messages implying that this interface is not as
simple as putting a connector on the board and running traces to the
pins on the part.  Is there a good example of *how* you need to design
the target board to get JTAG emulation to work correctly?

Thanks,

James Dabbs