ATI apparently had some sort of adapter you could use that would allow you to output at HDTV resolutions. But from what I hear, it didn't work so well.
IO Data answers with a card that natively supports output at HDTV resolutions.
Now all I need is a HDTV!

IO Data Device Corporation will release the "GA-S8HD/AGP," a video card capable of outputting D4 video signals, in the back part of June. The price is 23,100 yen. Supported operating systems are Windows 2000 and XP.

This AGP video card supports AGP 8x. It uses a "DeltaChromeS8 Pro" from S3 for a video chip. With the HDTV encoding "Hi-Def Function" of the DeltaChromeS8 Pro, the card supports Component output of D2(480p), D3(1080i), and D4(720p) video.

The chip has a 300MHz core clock, 128MB of DDR SDRAM for video memory, and a 600MHz memory clock. The maximum supported output resolution is 2048 x 1536 (Analog RGB)/1600x1200 (digital). Output ports are DVI-I, S-Video, D-Sub15 pin, and it also supports multi-display output (WinXP o­nly).

A D-connection convertor cable and video convertor cable is also included. Sega's o­nline RPG, "Phantasy Star o­nline: Blue Burst" (15 day free trial) is also bundled.



Inspired by:
http://www.watch.impress.co.jp/av/docs/20040609/iodata.htm

Press Release:
http://www.iodata.jp/news/2004/06/ga-s8hdagp.htm

Product Information:
http://www.iodata.jp/prod/multimedia/ga/2004/ga-s8hdagp/index.htm