Hi, the most painful part of a visit to the dentist is if he has to drill a tooth before filling. Its been a long time since I have had to undergo this pain, has there been any new advancement to make the drilling painless?

Yes there have been advancements made in medical technology for this purpose.
Here is an extract that you may find interesting and useful.
New Ways to Drill Teeth

Several new dental drills are now available that produce less than one-third of the harsh sound and very little vibration compared to the drills available for the past 40 years. If you require any extensive dentistry, ask your dentist if he can treat you with one of these new drills.

Painless drilling is really not drilling…it does not involve the dental drill or rotary cutting instruments. There are two popular technologies for painless drilling:

Air abrasion systems use tiny abrasive particles suspended in a high-pressure air stream to cut the tooth. Air abrasion is most effective on very small cavities on the biting surface or outside surface of the tooth. In addition to its whisper quiet sound, air abrasion’s biggest advantages are that less tooth needs to be drilled and that it does not contribute to crazing of the enamel the way the traditional drill can. In most cases, anesthetic isn’t required for air abrasion and the patient will experience the feeling of cold air being blown on the teeth. Air abrasion is a bit messy, but more affordable than the laser

I got this info from - www.robstrain.com/dental_fear.htm

Hey thanks, I am a bit of a coward, when it comes to the dentist's chair. I shall make sure the new equipment is available in the dental clinic I visit.

You are welcome!