Unless you live in a cave (or North Korea), you probably heard buzz earlier this week about Steve Jobs’ keynote announcing the new iPhone 4. Like a true geek, I was following along with the Engadget liveblog and found the new upgrades to the iPhone 4 camera really exciting (bigger backlit sensor, upgrade to 5MP, 720p HD video – more here).

And if you follow photography even casually, it’s hard to ignore the buzz about each new iPhone app that hits the street. The iPhone is already one of my favorite cameras in a pinch, and many of the new apps are super fun. Heck, even designer Andy Spade (of Kate Spade / Jack Spade fame) released an entire book of whimsical and inspiring photos, shot with his iPhone.

One of my favorite new toolkits is the retro Hipstamatic app, which mimics the look and feel of old vintage toy cameras. Its crazy cross-processing-esque colors satisfy the kid in me, and paint the Brooklyn landscape in a new way. I’ve noticed several of the photographers in our Flickr pool are using the app too — check out a few beautiful shots below.

Do you have another favorite app to share? Leave us recommendations in the comments below!

“Holding On,” by Joel Zimmer:

Untitled, by Amy Durocher:

“Coney Island Moon,” by cootiegarage:

Untitled, by R.Lombardo:

“Manhattan & Queens,” by Joel Zimmer:

Untitled, By Amy Durocher: