00:08.0 Multimedia video controller: Internext Compression Inc iTVC16 (CX23416) MPEG-2 Encoder (rev 01)
Subsystem: Hauppauge computer works Inc. WinTV PVR 150
Flags: bus master, medium devsel, latency 64, IRQ 193
Memory at c8000000 (32-bit, prefetchable) [size=64M]
Capabilities:  Power Management version 2
/bin/dmesg |grep Initialized
ieee1394: Initialized config rom entry `ip1394'
ivtv0: Initialized Hauppauge WinTV PVR-150, card #0
[drm] Initialized drm 1.0.1 20051102
[drm] Initialized radeon 1.25.0 20060524 on minor 0
Are you building ivtv from source or from ATRPMS? Try ATRPMS if the source didn't work. Make sure the firmware is installed as well. The wilsonet Mythtvology might be good as well.
I've never had so much trouble getting things to work in Linux since switching to fc6. At first it was the kernel mismatch problem then AIGLX wouldn't work with fglrx drivers and now I can't use tvtime because its not compatible with ivtv drivers. Luckily my fc4 box still does everything I want but without support.