Given the avalanche of new smartphones this fall, there's a good chance that your data use is about to spike as you put that fresh hardware through its paces. If so, AT&T might just have you covered. It's running a promo between September 28th and October 31st that doubles the amount of data you get with its Mobile Share Value plans, whether or not you're a new customer. Signing up for the special rates nets you up to a hefty 100GB per month of shared data at the high end. However, the starter offer is arguably the best -- $130 per month (plus line fees) gets you 30GB to play with, which should hopefully accommodate your family's Netflix viewing habits. AT&T's deal isn't necessarily as sweet as what you'll get with Sprint or T-Mobile, which start at a respective $100 and $140 per month for roughly the same service. However, it's competitive enough that it could keep you on Big Blue's network for a little while longer.