When will NBC announce the audition cities and dates for 2012 America's Got Talent?

The title says it all but to emphasize when (please give an approximate date within a week) will NBC.com post the cities and dates for the auditions for America's got talent and what song should I sing? My range is G3-E6 and I sing mostly for church so they're slow operatic songs. I've also done musicals so should I choose a song I do for church, a musical song, or a song that I can play on my guitar and sing like for example, Jolene by Dolly Parton?