Ask HN: What to expect and how to launch a non-gaming iPhone app?

Hi HN,

I'm about to launch my productivity/utility based iPhone app - JustRemindIt (http://justremindit.com) in just few weeks. It's a voice call based reminder app. Simply type message and reminder details, and it will remind a receiver via a voice call. I've demoed it to many people during development phase and everyone thought it's a really cool app. But I've this feeling that, however cool it is, it's not cool as playing games. App store, which is predominantly dominated by Gaming app success stories, I was wondering how can a productivity/utility based app make success? I've read few posts on HN about iPhone app launch marketing, but many were targeted for gaming apps. So what steps shall I take to launch productivity/utility app successfully to generate initial buzz?

Also, in the long-term, what shall I expect (revenue, download wise) from a productivity/utility based apps? Can anyone share their experience in launching non-gaming apps, and seeing successful results?

PS: This is my first iPhone app launch. The app will be FREE to download, but users will have to buy reminder credits via in-app purchasing to send reminders. There are different packages based on number of credits that you can buy.

All suggestions and comments will be very helpful.

Thanks! Aditya