5:50 PM -- The two largest U.S. telcos have been enjoying financial success on the heels of their strong wireless businesses, but could that growth be reaching its peak point? (See Wireless Fuels Verizon's Q1, Wireless Pumps AT&T's Q1, and Heading for a Fall?)

Some interesting numbers from UBS AG 's John Hodulik: While AT&T Inc. (NYSE: T) and Verizon Communications Inc. (NYSE: VZ) had another great wireless quarter, when you combine their adds with the estimated losses for Sprint Corp. (NYSE: S) and T-Mobile US Inc. , the U.S added only 1.4 million post paid wireless subscribers in the first quarter of 2008 -- down from the 2.6 million added in the same quarter of last year.

Unlike the landline sector, wireless isn't going to start shrinking. But if it's not going to get much bigger, and the wireless carriers are sinking billions into new wireless spectrum, where are all the returns going to come from? Will wireless data revenues really be that significant? Or will our cellphone bills go up faster than our FiOS bill? (See Verizon to Raise Prices, Cut Jobs.)— Raymond McConville, Reporter, Light Reading