Converting 24p or 29.97 to 1080i50
There are a few ways to convert 24p or 29.97i / 29.97p to 1080i50. You can do it through Compressor or After Effects.
With after effects you'll be using motion compensation and apply a pulldown.
The Crude But Quick Way
It's really nasty but you can just drop your 29.97 or 24fps footage into a Final Cut Pro 25fps sequence.
It will skip or duplicate frames here and there. Might not be a big deal especially an event or action shots. You'll see it on dolly and pans.
I get footage from editors all the time like this. It's better going from 24 to 25 because it just adds frames which you can just cut out later. Going from 29.97 to 25 is a bit nasty because it drops frames, now way of getting them back.