It’s been a long time coming, but on Thursday, Sling Media will finally ship a Slingbox capable of handling HDTV content. Some previous models have supported component-video, but this is the first Slingbox capable of streaming true high-definition video.

Sling’s Slingbox products enable you to stream live TV from a source in one room in your house to any another, or to a PC or smartphone anywhere in the world. Although Sony was first to market with “place-shifting” technology (the LocationFree TV line), and Monsoon Multimedia was the first manufacturer to offer an HD-capable device (the unfortunately named HAVA HD), the Slingbox line has captured the lion’s share of the market.

Dubbed the Slingbox Pro-HD, the new device features a built-in ATSC tuner capable of receiving over-the-air digital and digital cable TV channels (Clear QAM only; the tuner won’t stream encrypted content from premium channels such as HBO).

The Slingbox Pro-HD can also be connected to the analog video output from a DVR, set-top cable box, or HD satellite TV receiver (which would enable you to stream any content). The new box supports both standard (4:3) and widescreen (16:9) aspect ratios. Streaming HD content over the Internet to a remote client, according to Sling, will require broadband upload speeds of at least 1.5 megabits per second.

In addition to its built-in tuner, the new box features composite, component, and S-Video inputs, and both analog and multi-channel 5.1-channel digital audio via S/PDIF. An integrated looping circuit enables these signals to flow back out to a local TV or home-theater setup. The device does not, however, support HDMI.

The Slingbox Pro-HD will sell for $299.99 in the U.S. ($329.99 in Canada) and will be available direct from Sling Media as well as many online and brick-and-mortar retailers, including Amazon, Best Buy and Fry’s.