I was looking for a good tasks manager for iPhone but also something that would sync online. Most people that own an iPhone use the "Things" app that syncs with the Mac program "Things." I wanted an app that would sync online only. I tried a few other apps but nothing really worked until I found GeeTasks/GeeTasksPro. GeeTasks will sync with your current or future Gmail or Google apps calendar account. GeeTasks has 3 versions in the app store.
I tried the free version before upgrading to the Pro. The free version has adds and will not sync with a Google Apps account. The Pro version will sync with all Google accounts and no adds. The great part about the app is it will sync over the web every time you open it. If you like Google Tasks this is the perfect app.