What kind of Mac are you currently using? Because the 23" Apple Cinema HD Display uses an ADC connection. No recent Mac uses that kind of connection.
You may be misidentifying your display, as the 23" Apple Cinema HD Display was introduced in 2002 and discontinued in 2004. So, it would be unlikely that you bought it new in 2008.
23" Cinema Displays (note: no HD in the name) use DVI connections. They could be used with a Mini Displayport to DVI adapter, plugged into one of the new Mac Pro's Thunderbolt ports that double as Mini Displayports.
If you do have that kind of display, with the "HD" in the name, you would need an adapter that has been out of production for years. E-Bay would be a likely source.
http://www.ebay.com/bhp/apple-dvi-to-adc-adapter