My daughter's second concert was Wilco. (Her first was Dan Zanes.) She loved it! I think that a lot of Wilco's songs can be enjoyed by kids. My daughter loves a bunch of them, including "Spiders (Kidsmoke)" and "Hummingbird" from the last CD, A Ghost is Born. "I'm A Wheel" from that same CD is pretty great for the kiddles, too. But of course there are a handful of songs that were created kind of sort of with kids' in mind. The Mermaid Avenue CDs that took Woody Guthrie's lyrics and re-birthed them into something anew with the help of Billy Bragg aren't exactly for kids, but songs like "Hoodoo Voodoo" had to be sort of initially thought up all those years ago by Woody for a kid, or at least a kid at heart. My kid loves "A Magazine Called Sunset," which I think came off a web-only EP, so I included that here too. If you like these, don't overlook Wilco's song, "Just a Kid" from the Spongebob movie soundtrack. It's not their best song, but it is fun and definitely for the kids.
Wilco with Billy Bragg, "Hoodoo Voodoo"
Wilco, "A Magazine Called Sunset"
Ther Mermaid Avenue CDs can be bought most anywhere, here they are on Amazon. Buy single songs, or their Spongebob track on iTunes. And see/hear more Wilco at WilcoWorld.