Problems with ICP with more than 1 device

Hello, please help me, I am trying to make a sketch with more than one SPI devices in the arduino duemilanove.

That protocol needs 4 ports, one the clock, two the communication UP and DOWN the arduino, and the last one "slaveselect", to make possible be more than 1 device using that protocol at the same time.

OK, that ports usually are from 10 to 13, the problem is when you want to use two devices at the same time.

I searched and found that 3 of that 4 wires can be used for all the devices, but the last one "slaveSelect" needs to stay alone, for each of the devices

The problem is that when I want to change that port (usuali digital port 10), to 9 or 8 (changing in the program the port obiously), the program brakes down

That happend to me reading a SD card, with the ethernet shield, or whatever, but in some post in I see like the people talk about changing that port

┬┐How can I connect at the same time more than 1 SPI device in the Arduino?

Thank you and sorry for my english.