From SCM Microsystems:

In this video we show you how to install the software that allows you to use your Multicert smartcard reader. CAC Developer Kit (CDK) - This CDK contains documentation and software needed to interact with the CAC's machine-readable media smart card ship, magnetic stripe, and barcodes. The kit is designed for developers of client-side workstation applications using the CAC data and services, and developers of card-side applets and middleware.

Update your SmartCardReader USB drivers for model SCR3310.

SCM's SCR3310 and SCR3310v2.0 are small and ergonomic USB smart card readers, with backside mounting holes. The readers are ISO 7816 compliant, and can be used for cards in ID 1 card format.

This installer contains PC/SC driver and CT-API library and can be used for SCR531 USB, SCR331 CCID, SCR333, SCR335, SCR355, SCR338, SCR3310, SCR3311, SCR3320, SCR3340, @MAXX Family and SCT3511

SCR331 and SCR531 users note that only readers that have CCID firmware are supported. Readers that have firmware Rev 2.0 and above are CCID. This driver may also be used with the following third party products: Goldtouch ErgoSecure SC 2.0 keyboard, Datakey DKR830. If the host is running Windows 98 SE or Windows Me, ensure that Microsoft Smart Card Base Components are installed on the host before atempting to install the drivers.

What do you need to know about free software?

Best Cac Reader For Mac

This is similar to a CAC Reader which I had at work, and, well, it works great. I've been using this in conjunction with WaterFox (64-bit version of FireFox), originally on Windows 7 and now on Win8, and have been able to access the five or six sites I'm required to check regularly.
Windows 8 (and possibly 7) have built in reader capabilities, although these definitely operate on a lower level than actual CAC Reading software (of which there is the usual ActivClient and a freeware program, though all of my experience is with ActivClient). Setting up this software and getting everything to run might take from 15-30 minutes depending on which resources you're using, but once you're past that initial setup, you don't have to touch it again.
With the growing emphasis on websites for document and records management and communication, this card reader is almost a necessary investment. Its simplistic design also means it comes at a very reduced cost... other readers might not be that much more expensive, but this is a sturdy device and I'd say it's worth it to save yourself the extra 20 bucks.