Any drive you insert in the docking caddy should appear as a normal USB connected drive, regardless of whether you connect it to a PC or a Mac. You shouldn't need any software to read from or write to the drive.
If you intend to clone a drive in your machine to it, you will need software for that purpose. Acronis True Image works well for PC's. I've heard that Carbon Copy works for Mac's, but I'm not a Mac user so I can't confirm that from personal experience.
Cloning a drive through a USB port takes much longer than cloning to a drive connected directly to a SATA or PATA port in the machine because the transfer rate is so much slower via USB. For example, cloning my desktop drive takes about 20 minutes while cloning my laptop drive through a USB 2 port takes almost three hours.