depends on the frame rate scaling of the video processor in the television (or in the receiver)
if your television can take 60 frames per second and upsample (as well as interopolate) the interlaced signal.. the progressive frame rate would normally be 30.
but
with the upsampling, new frames would be created from 'key frames' and bring the frames per second back up to 60.
technically.. the television would be working at like 120 frames per second interlaced, plus or minus any frames to help create the upsampling.. that is much more of the reason why the new televisions dont play well with live video games.
'key frames' are plenty enough to get the same exact content viewed live.. regardless of the frames per second (60, 120, 180, 240)
but remember this..
you should only DOUBLE the frames per second.
if you try to triple the frames per second, the video processor will get confused inbetween key frames and ugly things happen.
could be a crash of the video processing..
could be an artifact visually seen of the video processing..
could be a nuisance that interferes with the inputs and the mental receiving of the synchronization for input to visual result.
a 1080i television can produce 1080p with full frames per second, or half of the frames per second.
hell..
the televisions can try to triple the frames per second and see stupid results (accompanied with a high lcd panel response time and the results really are seen as stupid.. or 'dull and lifeless')