The handset market will have much to be thankful for this holiday season, according to new reports out this morning from IDC and Strategy Analytics. IDC said manufacturer shipments increased by 5.6 percent in the third quarter over the previous one as promotions of older devices at lower prices — such as the $99 iPhone 3G — propped up demand. While the 287.1 million handset shipments were down 6 percent from the same period in 2008, the quarter-by-quarter increase in shipments indicates that carriers and other retailers are expecting a better holiday season than last year, according to IDC.

Meanwhile, Strategy Analytics is predicting a 3 percent increase in global shipments in the final quarter of 2009 over the year-ago period, reaching 300 million units. The increase would mark a return to positive growth for the first time since the third quarter of 2008, the market research firm said. Shipments in the three months ended Sept. 30 fell 4 percent from a year earlier, indicating an upswing after an average year-over-year decline of 11 percent over the previous three quarters.

Those figures are music to the ears of OEMs, of course, which have suffered through a brutal few quarters as the worldwide economy tanked. But they also indicate a huge ray of light at the end of the tunnel for operators, as even cut-rate smartphones require ARPU-boosting data plans. And vendors are hoping to build on that demand with new smartphones such as T-Mobile USA’s myTouch, and the Droid and BlackBerry Storm 2 from Verizon Wireless. All of which should lead to a very merry holiday season indeed, for both manufacturers and carriers.