Sure, they said it would be available immediately, but they lied. Now, the lie has become the truth, and the truth is just a fleeting dream, caught in between worlds we can't hope to understand, let alone grasp. Meaning: go download iTunes 10 with Ping.
Update: We've added direct download links below. Thanks commenters!
Update 2: A word of warning -- if you activate Ping, it will potentially make all of the nasty reviews you've written available for the world to see. So now they'll know who panned their recording debut and ruined their career.
Update 3: Got an iPhone or iPod touch with iOS 4 on board? Ping may have magically appeared in your iTunes app, ready to help you wax introspective on the go. [Thanks, Kruze]