I've added a few more links recently there on the right and I wanted to point out a few that focus on other ways to disseminate children's music.
Spare the Rock, Spoil the Child is a kids' music radio show broadcast out of Massachusetts but also with a weekly podcast. Bill Childs and his 6-year-old daughter Ella spin a bunch of great kids-related tunes, never failing to begin and end with a They Might Be Giants song. That, frankly, would be enough for me, but I've watched his playlists over the past few months, and they've always been quite cool. Do check 'em out.
Pancake Mountatin is a kids' music TV show broadcast in the Washington, DC area. I first stumbled across them last year and their guest list is still pretty amazing. They don't really play kids music -- they bring in "adult" bands and have them play for kids and their minders. Generally the bands play more "adult" music, which I'm not wildly enthused about, at least for the predominant musical selection, but their guest list -- The Arcade Fire, The Go! Team, Metric, Ted Leo, and the like -- is very indie-rock-friendly.
Finally, TV For Tots isn't focused on children's music at all -- the sharper ones among you will have figured out that it's focused on children's TV. It can be argued, however, that Noggin is the single biggest factor in the recent boom in kids' music. No Noggin, and I doubt that Laurie Berkner is selling her DVD in every Starbucks in the country. That's why I check this site out.