I'm not sure what "highly recyclable" means, but it's clear that Apple is at long last starting to take this important issue seriously--all those toxic chemicals are bad for the planet, bad for the manufacturing crews, and might just be bad for the end users. The company has promised to make similar changes to its entire product line by 2010, so look for more announcements like this in the next few Apple product launch extravaganzas.
Specifically targeted: reducing lead, cadmium, arsenic, mercury, and PVCs in
computers and home entertainment components. Apple has also been giving some
thought to its packaging, opting for biodegradable materials and reducing
unnecessary bulk wherever possible. This summer’s 3G iPhones shipped in
Styrofoam-free trays made from potato starch.
Arsenic-free display glass
Construction free of Brominated Flame Retardants (BFRs)
No use of mercury
No use of PVCs
Highly recyclable metal casing
For more on the topic, see this ABC News story and the official tech specs from Apple.