The big switch to all digital television comes on February 17th of next year, when everyone will need some form of digital reception to be able to watch local television.
In the meantime local stations are already broadcasting in digital, and often with multiple program streams. WSFA, for instance, broadcasts Weather Plus on our DT 12.2 channel, and we began just last week broadcasting The Retro Television Network, classic family programming from the past 50 years of TV, on WSFA DT 12.3. Other stations in the area also broadcast multiple programming on their digital channels.
If you watch local television with an over-the-air antennae, you could be watching those extra channels now... with a converter box. Digital television converter boxes are available at local electronic retailers, and the government is offering a $40 discount coupon toward their purchase.