This story is a bit old but it seems that Blu-ray is starting to slightly pull ahead of HD-DVD.
According to Next Generation, it seems that "Blu-ray movie unit sales stand at just over 439,000 units in the US, while total HD-DVD sales are just under 438,000 units. Blu-ray currently stands as the number one new DVD format in unit and dollar sales in the US, according to research firm NPD Group."
HD-DVD players may have gotten on the scene first in the spring of 2006, but Blu-ray players which came out "in the summer 2006" seem to be gaining market share due to the fact that software for the product appeals to more consumers. In fact, "Sony expects the new generation movie sales gap to widen throughout 2007."
Apparently, "sales of the Blu-ray enabled PS3 spurred a relative Blu-ray movie buying frenzy in January following the console's mid-November launch." Apparently, "Blu-ray titles outsold HD-DVD titles close to three-to-one during the second week of January."
In addition to this, Sony "currently lays claim to 40 percent of the the Blu-ray player market with the PS3 and the company's $1,000 BDP-S1 standalone player."
Also, Sony has "shipped 2 million PS3s worldwide by mid-January, with 1 million of those shipped to the US by the end of 2006."
Don't think that HD-DVD is laying down. It was only last November that "Microsoft launched an HD-DVD add-on for the Xbox 360, which had sold 92,000 units in North America as of the end of December 2006, according to the NPD."