Using a 27" iMac as Monitor for PC

I am building a PC for Network Attached Storage (NAS) using FreeNAS:

http://www.freenas.org/

Once it's all set up I'll just use the web/network interface to manage it. But, as I assemble the PC I'll probably need a monitor to make changes to the BIOS settings.

I'm wondering whether I can use my iMac (iMac11,3) as a makeshift monitor for the PC. Apparently it's possible to do this if the PC has a Mini DisplayPort.

http://support.apple.com/kb/HT3924

My PC has the followoing video ports:

- VGA

- DVI

- HDMI

Can anyone tell me whether I can use my iMac as monitor to a PC with one of these ports?

If so, can anyone recommend a cable to do so? For example, this Mini DisplayPort <-> HDMI cable says it won't work for my purposes:

http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10428&cs_id=1042802 &p_id=5311&seq=1&format=2

"This device is not Bidirectional. It can only connect a Mini-DisplayPort source to an HDMI® display. It will not work in reverse."

I want to display my PC's VGA, HDMI, or DVI as the source to my iMac's Mini-DisplayPort, not the other way around.

Thank you for your help.

- nello