Do you have that superboot folder (the one used to unlock/root) on your Mac? If you do, you should be able to drop the file into that folder, then use the adb command to push it to /sdcard.
You can use the android file transfer located at Android.com
This is a program that allows drag and drop adding files.
otherwise:
place the ROM in any folder with adb in it, then type:
Code:
cd /Directory/of/folder/
./adb push /ROM.zip/ /sdcard/
then you can boot into recovery and flash it. If you have fastboot, you can place it in the same folder, as well as a copy of any recovery and do the following without overriting the stock recovery.