Yes, that's possible! Install and launch Remote Buddy 2 and plug an inexpensive Flirc USB receiver into a free USB port of your Mac. That's all! Remote Buddy 2 will automatically recognize the receiver and start responding to button presses from your Apple Remote.
You can also use other IR receivers with Remote Buddy 2 for this, but only Flirc USB provides firmware-level support for and integration with Remote Buddy 2 to deliver special features for Apple Remote, like wakeup support.