Ticketmaster announced a partnership with the iTunes Store today which will allow their customers to receive a free song from iTunes, starting this summer. A "music sampler" of the artist they're going to see will also be made available.
In addition, iTunes customers who pre-order certain albums will be able to buy concert tickets before the general public. You may remember that Apple tried this last year, and it didn't to very well. According to Sean Moriarty, president and CEO of Ticketmaster, that won't be the case this year:
"By providing direct links to iTunes, the world's most popular online music and video store, we're giving iTunes and Ticketmaster customers the opportunity to buy concert tickets, and explore and purchase great music..."
Also, look for iTunes + Ticketmaster gift cards this summer, which will be redeemable with Ticketmaster and iTunes. They'll cost $50US.