The World Wide Leader has a pretty good U20 World Cup line up between ESPNU and their broadband service, ESPN360.com. They're going to broadcast every match from Canada, with ESPNU showing all the U.S. (and a smattering of other 1st rd. games) and knock-out round matches.
The only thing that remains to be seen is who will be doing the on-air play-by-play and color. My hope is for the Champions Leauge crews, but I'm bracing for the worst. ESPN has been known to disappoint.
ESPN To Air U.S. U-20 World Cup Matches [Soccer365]