DS was constantly dribbling and had a red bum and red cheeks on and off from about 3 months, but didn't get his first tooth until 6months. Now at 10months he has just got his third. I can see about 3 or 4 more teeth just sitting under the gums though so they probably won't be too far away either.
The tell tale sign of an impending tooth in our house is a runny nose. The day before and day of a tooth cutting DS's nose runs like a tap.