A local paper's tech blog reviews Digital-TV converters available locally. His preference is the "Digital Stream DTX9900 sold by RadioShack". I need to spend my vouchers before they expire, so I'll probably follow his lead here.
From what I've read elsewhere broadcast digital may require a fairly expensive antenna investment. So the converters are only a part of the cost. We have very cheap antennae; I'll report on what we find in our real world testing. All we need is for one sports channel to come in so my son can spend his tv-time credits.
Update 5/4/08: Bloody 'ell, it worked.