http://docs.info.apple.com/article.html?artnum=307054
I was just researching if I upgrade my Imac and Powerbook but this is a no go at least for the Imac. The guy who wrote the Enabler for older macs wrote that they decoupled Itunes and Front Row and when I googled if Airports Express would still work the above came up.
A bit disappointing.
Cheers
JK
BS9000, BS2300, BC2, BL2500, BL3, Bl2, BS1, BV8, BC4, A8