Good news, unless the contempt charge was tried (court trial), it is not criminal, or a conviction. It is an administrative punishment imposed by the judge, so you would have no criminal record. At worst you would have an arrest record and you could avoid that in some courts.
Again, the cell phone going off was an accident in the same manner as passing wind. If you are prosecuting cellphone ringer abusers you would also have to prosecute the chronically flatulent in the courtroom.
If Benjamin Franklin were alive he would be posting here, advocating the same position. I suggest that you read Mr. Franklin's seminal work on the subject, "Fart Proudly," which is available at the link below. The girl is being treated improperly.
http://www.amazon.com/exec/obidos/ASIN/089804801X/qid=1101173344/sr=2-2/ref=pd_ka_b_2_2/002-8997366-8328859
Or get your bell rang by some toothless lumberhead while sitting in jail.