Our latest iPhone App just hit the store. We updated the graphics for retina display, and to more closely match the new design direction of the app.
You can now email campaign stats to co-workers. There is a "Normal" email, which lists basic things like opens, bounced, and click rate as well as a "Detailed" email, which emails a link to your campaign’s VIP Report so you might want to go set those up with your custom branding.
The previous version was built for use with one data center, but MailChimp runs on multiple data centers (for redundancy), so some users couldn’t log in. That issue’s been fixed along with a few other little bugs.
You can also log in using your API key now, which is great for folks who use Google Apps to log into MailChimp.