ARIEL74  The concept behind this program is great. But I live in Frankfurt, Germany, and it seems that the program does not recognize cities outside the US and so cannot search for shows in Europe.

Could someone (the developer?) confirm this? and if so, how about an update that does that? Thanks.  
(Version 2.4)

YOSHINATSU  Brilliant. Could have had a more native look, but HEY, it's free!

So what are you waiting for?? Give it a try!  
(Version 2.4)

SURFSPIRIT  Excellent idea! And the integration with iTunes is very clever, but needs support for international tours and countries. Also the interface needs a more mac os style/integration. But here's a product with great future! Congratulations!  
(Version 2.4)

CLAUCLAU  Sure it's a handy application.

But I tend to point out what's missing mostly, maybe in order to give a possible good input.

So basically what this application does is to show is to scan the itunes library / Favourite artists and show the upcoming concerts. That would be 870 songs in the itunes Library at least. 1 song for each artist.

It could be smart enough eventually to reveal some cover bands playing (say for example Ella Fizgerald cover band), but it won't recommend any other band which would play the same style of that kind of music. On the other hand this iConcertCal would avoid sudden gigs that you wished you would have gone, but you couldn't plan for. Unlike LastFM gigometer, which even restricts the search by town.

Sure is that both of these applications avoid signing up to newsletters resulting in a huge amount of email notifications.  
(Version 2.4)

CA  Awesome! I got a little window telling me about an upcoming CD. Really a brilliant app. And it’s free!

Congratulations! I love it!  
(Version 2.1b2)

ABIGPOTOSTEW  This application is great, I just downloaded it and it runs perfectly. I'm running 10.5.2 and have found to errors yet. It handles my 35GB music library quickly and efficiently without any crashes. Awesome application!  
(Version 2.1b)

UNUSUAL FALL  Absolutely great.  
(Version 1.2)

MDAMLI  Excellent idea executed perfectly.

However, I would really love to have it internationalized, so one can list concerts within a country+city, ie. Norway+Oslo.  
(Version 1.2)

MAC-DEVIL  Fine PlugIn... but please make it better > German concert locations!  
(Version 1.2)

WOODEN BRAIN CONCEPTS  I have not tried this, but as a developer of iTunes related products (Cast Away, iDupe, OmniGrowl, etc.), let me say that my guess is that this cannot work with very large libraries the way it is probably designed. Most likely it gets a list of all your artists and then searches for matches on on-line databases. OnTour has a dashboard widget that works that way and has the same problems. Developer -- please correct me if I'm wrong.

OmniGrowl, which features concert notifications also, takes a different approach to cope with large libraries -- it periodically searches the online data sources and then searches your iTunes library for matching artists. But it does this only once hourly and does not attempt to get a list of all artists (which is guaranteed to hang iTunes with large libraries).  
(Version 1.2)