I think Dave and Alex got tvout working in radeon a month or so ago. Most of their testing was on 5xx parts IIRC but I *think* it should work on 690 as well. Last I saw was that NTSC was working pretty well but PAL was only outputting in black-and-white.
r6xx was working well, r5xx less so. I never got a chance to test rs690 or r7xx. Both PAL and NTSC should work on r6xx at least.
FWIW tv out doesn't work properly on my r5xx or r6xx.
I wonder if it's something to do with using an analogue monitor as well - there does seem to be some confusion between tv and monitor on r5xx for me. With tv out disabled but s-video connected I don't get a display on the monitor and get junk on tv. With tv enabled I get a green monitor display (not solid so it's useable) but still no tv.
On r600 it's slightly different, with tv connected monitor will work without tv enabled. With tv enabled both tv and monitor are green tinted.
I can almost workaround on r6xx as the vesa driver works OK. If I run vesa first then run radeon it works. It's not quite right @ 1024x768, though. With vesa I get the full screen displayed on tv, but radeon only clones 1024x576 ish (it was a while ago I tested).