I had Scott over at Mythermos.com send me an email about this site a couple months back. I am finding out how useful it is right now as we track artists on tour or just to find out what tour dates are listed for select artists. The site is called Songkick. They have many many artists listed and those on tour have (on Tour) denoted next to the artist’s name. If you click on an artist that is on tour it recommends other artists like them, besides giving the tour dates for that specified artists.
They are also creating widgets for blogs like The Dead Hub. For instance, their widget will list all the artists that are mentioned in the blog and the tour dates. Plus if you are not a blogger, you can download the “Songkicker” that is a plug-in that tracks the tours on artists in your music library.
Pretty nifty for someone like me who needs to know who’s on tour and where they are playing.