Currently Being ModeratedMay 25, 2011 3:47 AM (in response to Reuben Feffer)
I've kind of found an answer to my question, but I'm not totally satisfied. Basically, yes, you can use one Apple Wireless Keyboard with an iMac and iPad, but obviously not at the same time.
To switch the Apple Wireless Keyboard over from working with the iMac to working with the iPad, you first have to "Disconnect" the keyboard in System Preferences > Bluetooth. This frees up the keyboard, making it available for the iPad to access.
Currently Being ModeratedMay 25, 2011 4:21 AM (in response to Reuben Feffer)
I see you have apparently answered your question. A Bluetooth device may only be paired with one thing at a time.
BarryiMac 27" 3.2 GHz Intel i3/4 GB, DSL, Firewire HDs, Mac OS X (10.6.7)
Currently Being ModeratedMay 25, 2011 9:30 AM (in response to Barry Hemphill)
It seems that a device can be paired with multiple things at a time but only connected to one. Both the iPad and the iMac remember the Wireless Keyboard, and don't need to be repaired (by entering a security number).
Currently Being ModeratedMay 27, 2011 6:41 AM (in response to Reuben Feffer)
How about the converse? Can you pair two bluetooth keyboards to the same machine and have them both work at the same time? I'm a touch typist and I'm interested in spreading my arms (shoulders) apart by having two simultaneously functioning keyboards.
Currently Being ModeratedMay 27, 2011 8:16 AM (in response to stephenfromann arbor)
I haven't tried that, but yes, I think it would work. I already have a Wireless Keyboard and a Magic Trackpad paired with my iMac, so that's two bluetooth devices paired with one machine. I don't think the Mac really cares what the devices are, they could be keyboards, mice, trackpads, phones, etc.