Morning program, Good Morning America, will be launched in HD in September beating its competition to the high-def format. NBC's Today show most likely won't make the transition to HD until early next year while CBS doesn't currently plan on offering its Early Show in high-definition at all.
"GMA ’s embrace of HD is an important milestone for the still-fledgling broadcast medium. Weekday network programming in HDTV has been nonexistent, with the exception of CBS’ HD broadcasts of The Young and the Restless . The costs associated with HD production, typically adding an average 15% to a program’s production budget, and the belief that the heavily female daytime audience is not clamoring for HD (most HD programming centers on sports and movies, both which have strong appeal to male viewers) have made weekdays a virtually HD-free zone. But ABC says it has detected a burgeoning interest among daytime viewers in the broadcasts."
source: Hoover's Online