I got the bulbs from NAPA. They were the only auto parts store I could find that sells them. They are pretty easy to replace. Just pull the dash trim off and the DIC slides out with the bulbs accessible on the back.
Are they plug in or soldered on? My left one works intermittently...could just be a loose connection though. Sometimes if I kinda tap it the light will come back on so i think it's just the connection.
2001 Regal GS, PLOG, 3" DP, 1.9's/L76 springs. 21* of timing on a 3.4"