Both Dell and IBM endorse using a 50/50 mix of water and isopropyl alcohol and a very soft cloth, like an eyeglass cleaning cloth you can get at any drugstore.
Here's Dell's instructions:
From the dell Premier Website:
Cleaning Your LCD or Flat Panel Monitor:
CAUTION:
Isopropyl Alcohol is a flammable liquid.
Never spray or pour any liquid directly on the LCD panel.
Do not clean the screen while the system is on.
1. Shut down the computer.
2. Disconnect power to the system or monitor.
3. Wipe the LCD or flat panel screen gently with a soft dry cloth. If any marks remain, moisten the cloth with LCD cleaner, and then gently stroke the cloth across the display in one direction, moving from the top of the display to the bottom.
NOTICE: Do not use any of the following chemicals or any solutions that contain them: Acetone, ethyl alcohol, toluene, ethyl acid, ammonia, or methyl chloride. If you have a different chemical or solution and are not sure whether it is suitable, do not use it. Using any of the chemicals in the previous list may cause permanent damage to the LCD or flat panel screen. Some commercial window cleaners contain ammonia and are therefore unacceptable.
4. Be sure the LCD or flat panel screen is dry before closing it or using the computer.
There are many cleaning solutions sold specifically as LCD cleaners. You can use these to clean LCD screens on Dell notebooks. Alternately, you may use a 50/50 isopropyl alcohol (IPA) and water mixture. Microfiber cloths such as those used to clean eyeglasses are excellent for use with LCDs.
---------------------End of Dell instructions-------------------------------------
Here's IBM's:
The TFT LCD screen is a delicate device that requires careful handling. To keep the LCD from being damaged keep these precautions in mind:
Do not place anything heavy on your ThinkPad system.
Do not scratch, twist or hit the surface of the LCD screen.
To clean, gently wipe the LCD with a dry, lint-free soft cloth.
Note: Antistatic LCD cleaning cloths and Kim Wipes are also acceptable alternatives.
If a stain remains on the LCD, moisten the dry, lint-free, soft cloth with water or a 50-50 mixture of isopropyl alcohol and water that does not contain impurities.
Attention:
Never spray or pour any liquid directly on the keyboard or LCD panel!
Wring out as much of the liquid as you can.
Wipe the display again; do not let any liquid drip into the computer.
Let the LCD dry before closing the lid.
Attention:
Isopropyl Alcohol is a flammable liquid. Do not use this cleaner near an exposed flame or when the system is on.
Links for verification:
http://premiersupport.dell.com/suppo...t?dn=FA1011125
http://www-307.ibm.com/pc/support/si...id=MIGR-4A2P54