The Summer Krush Web site's releasing only a few tickets each day at random times, so it looks like you have to continually check back. Sounds like a cheap way to drive traffic, something we'd never do on this site.
The Samsung Summer Krush concert series has hit several cities already, with a different artist at every stop (sorry about your luck with that Darius Rucker show, Nashville).
If that doesn't suit you, Power 92 is giving away tickets as well.
Whichever route you choose, you need to act quick, because you don't want to be left Big Pimpin' on the outside looking in.