Re: iMac Broadcast Delivery

You could shoot and edit in DV quite well on your iMac; many other students work this way. Use the appropriate Easy Setup and be mindful of field-order issues from any other sources you accept (such as motion graphics.)
Produce a DV master, check it on a video monitor, then have that dubbed to a format suitable for the network - I'd recommend Digital Betacam.
At every stage, work in widescreen (DV anamorphic) as this will help future-proof your film and give you more screening options internationally, which is the desire of most students. Check with the initial broadcaster about how they want to present your film: 4:3 centre-cut from your 16:9 master or as 16:9 letterbox. That way, you know, before you begin, whether to use all of the widescreen format, or to confine major elements including graphics to a 4:3 safe within 16:9.
Far easier to get 16:9 into a 4:3 format, than 4:3 into a 16:9 format.

Neil.