Dear Aunt TUAW: Is AT&T killing my iPhone?

dear Aunt TUAW, I just received this text from AT&T: “Network changes may soon impact your 2G phone service. Exchange 2G phone @ AT&T store w/free 3G AT&T U2800A phone by 5/15 & avoid service impact.” I wonder what this means? On the one hand, it’s an excuse to get a new iPhone; on the …