Mac Caller ID for OS X
"Is it possible to have a phone number display caller ID on my Mac computer monitor when I receive an incoming phone call? I am subscribed to call display with my local phone company and the phone numbers display on my home phone."
Mac Caller ID is harder than it used to be, because most Mac hardware no longer includes a modem port for connecting a phone line. In the past, you simply needed to plugin your phone line to your computer, download caller ID software, and Mac OS X would happily inform you each time you received a phone call. To add caller ID to your Mac now, you need an external USB modem along with software.
External USB Modem hardware
Apple used to sell an external usb modem for MacBook and iMac hardware. Apparently Apple concluded there's no market for selling USB modems, because their online store no longer carries them. You will need to purchase a USB modem from a third-party vendor, like the U.S. Robotics 56K USB Modem available from Amazon. Once you have the USB modem hardware, you also need software to make it work.
Mac Caller ID Software
The only currently supported Mac caller ID software I've seen is CIDTracker, which notifies you when you have an incoming call as long as you have a modem connected to your computer. CIDTracker can also send you an email to let you know who called your phone when you are out of office as well, helping you avoid those important business calls.
While this doesn't directly address your problem, there is an interesting variation on this for iPhone. Phone Amego uses Bluetooth on your Mac and on your iPhone to show you who is calling your iPhone before you go to the trouble of trying to figure out where you put your iPhone. The software will also place a call on your phone, from your Mac, by sending the phone number via Bluetooth to your iPhone.