AVR-Chat

I want to put a row of 3 of these devices down...

I assume I should put a XTAL on the first, and run the at others off 
it's CLKO signal...

I need to program them all... I am told I can both program and debug on 
a JTAG chain... has anyone done it, and does it work?

the 12V only gets involved for parallel programming doesn't it?

What advantage/disadvantage would it be to take the SPI pins to a 
header so I could SPI program? Can I share all the SPI pins except SDI 
or CLK and use a single header and a multi-way switch on one signal to 
program the three in turn? 

Does the standard JTAG programmer have an SPI connector, or do I need 
yet another piece of hardware ?

TVM

David