Does anyone know how to hook up a real time clock to the arduino with the arduinix shield to keep better time. I'm running the 6 nixie tube clock code. I'm new to arduino. Do I need the code for the rtc after I set the time and have it wired to the arduino
You could use any Real Time Clock (RTC) module. For example the DS1307, because there a lot of example code for that RTC.
Here is a nice tutorial : DS1307 RTC tutorial
Once you set the time, you need code to communicate with the RTC. You have to retrieve the current time from it to be able to display it.
Every nixie clock uses and RTC, so there are examples.
Your could check some links of user projects: ArduiNIX™