The World U-17 Challenge doesn't get as much attention since it takes over the same time period as the more popular World U-20 tournament, but it's a solid tournament and one of the first opportunities to start seperating out the draft class for the following year. This year's event will be held on the moon. Just kidding, it's actually much farther away in Timmins, Ontario.*
The United States will send their NTDP U17 team, hopefully bolstered by a few additions as well. Seth Ambroz is an obvious candidate after helping the US win gold at the Four Nations Cup a couple weeks ago. It'd be interesting to see if they could add someone like Shane McColgan playing in the WHL for this as well.
Canada splits themselves up into regions for this tournament. Team Ontario has won the last two. Here is the Team Ontario roster. Michigan recruit Lucas Lessio and goalie Chris Festarini are the only two non-OHL players on the list. I think they might face some heavy competition this year from Team Pacific, who has some pretty good players. They've got four kids not playing in the WHL currently. I haven't bothered to check into their status as far as NCAA prospects, but you'd imagine they'd be on the radar if they avoid the WHL. The team from Saskatchewan and Manitoba doesn't have as many WHLers, but those provinces also produce much fewer college players that BC or Ontario. Quebec also has a team, but it's Quebec, so who cares.
(*I was going to make fun of Timmins a little more until I checked out their Wikipedia page. It's probably best known for being the hometown of Shania Twain, which, who cares, but also as the hometown of Paul Bellini(that's my second relatively obscure Kids in the Hall reference this week), the town where Stompin' Tom Connors got his start, and the hometown of the greatest cartoon voice actor ever, Maurice LaMarche. You produce the voice of Orson Welles on The Critic and Blue Falcon from Harvey Birdman: Attorney at Law, and that puts you in like the Top 3 of most intriguing things about Canada, right up there with peameal bacon and....nope, that's about it.)