Well, a good few years back the BBC broadcast a series on radio, called 'Tales from the Perilous Realm', aimed at children (its now available on CD). The series dramatised Tolkien's short stories, Farmer Giles, Smith, Niggle & 'The Adventures of Tom Bombadil' - this one dramatised the Old Forest/House of TB/Barrow Downs section of LotR. The series was adapted by Brian Sibley (who also adapted the BBC Radio series of LotR with Michael Bakewell) & one of Sibley's motivations for doing the series was the chance to dramatise the Bombadil section, which had been omitted from their LotR series.
The Giles adaptation starred Brian Blessed & is a very entertaining romp. Of course there's a lot of stuff in it that kids won't pick up on (some very clever scholarly jokes), but that doesn't matter, because they won't notice them. Throw yourself into the story - play it 'big' - & they'll love it.
EDIT
BTW it seems that Harper Collins are bringing out a collected edition of Tolkien's shorter fiction in Hardback this August
http://www.amazon.co.uk/Tales-Perilo...6930021&sr=8-3
Hopefully it will include the Baynes illustrations & the Roverandom colour plates by Tolkien...