I found this on the net and could not agree more:

The first Ten Commandments of cell phone etiquette, with amendments to follow:

1. Thou shalt not subject defenseless others to cell phone conversations. When people cannot escape the banality of your conversation, such as on the bus, in a cab, on a grounded airplane, or at the dinner table, you should spare them. People around you should have the option of not listening. If they don't, you shouldn't be babbling.

2. Thou shalt not set thy ringer to play La Cucaracha every time thy phone rings. Or Beethoven's Fifth, or the Bee Gees, or any other annoying melody. Is it not enough that phones go off every other second? Now we have to listen to synthesized nonsense?

3. Thou shalt turn thy cell phone off during public performances. I'm not even sure this one needs to be said, but given the repeated violations of this heretofore unwritten law, I felt compelled to include it.

4. Thou shalt not wear more than two wireless devices on thy belt. This hasn't become a big problem yet. But with plenty of techno-jockeys sporting pagers and phones, Batman-esque utility belts are sure to follow. Let's nip this one in the bud.

5. Thou shalt not dial while driving. In all seriousness, this madness has to stop. There are enough people in the world who have problems mastering vehicles and phones individually. Put them together and we have a serious health hazard on our hands.

6. Thou shalt not wear thy earpiece when thou art not on thy phone. This is not unlike being on the phone and carrying on another conversation with someone who is physically in your presence. No one knows if you are here or there. Very disturbing.

7. Thou shalt not speak louder on thy cell phone than thou would on any other phone. These things have incredibly sensitive microphones, and it's gotten to the point where I can tell if someone is calling me from a cell because of the way they are talking, not how it sounds. If your signal cuts out, speaking louder won't help, unless the person is actually within earshot.

8. Thou shalt not grow too attached to thy cell phone. For obvious reasons, a dependency on constant communication is not healthy. At work, go nuts. At home, give it a rest.

9. Thou shalt not attempt to impress with thy cell phone. Not only is using a cell phone no longer impressive in any way (unless it's one of those really cool new phones with the space age design), when it is used for that reason, said user can be immediately identified as a neophyte and a poseur.

10. Thou shalt not slam thy cell phone down on a restaurant table just in case it rings. This is not the Old West, and you are not a gunslinger sitting down to a game of poker in the saloon. Could you please be a little less conspicuous? If it rings, you'll hear it just as well if it's in your coat pocket or clipped on your belt.