Eberhard Rensch is the developer and owner of Pleasant Software, based in Offenburg Germany. The company's two most popular products are both iPhone apps: Birdie (a golf score application) and TwittMS (an application for facilitating direct messaging in Twitter). We sat down with Eberhard for a chat at the WWDC.

TMO: How did you get started in iPhone development?

Rensch: I have been developing software for the Mac for over 20 years. Mainly, I was doing contract work, writing specialized software for businesses. When the iPhone came out, I got my hands on one right away and knew I wanted to program for it. But I had to wait until the iPhone SDK came out before I could actually do it.

I instantly signed up to be an iPhone developer and wrote Birdie. It was one of the first 500 apps submitted to the App Store and was quite successful. I made enough money in the first month of sales to break even with what it cost me to develop the program. Even now, it is among the top 5 most popular apps in the European App Store.

TMO: That's impressive. Are there other competing golf scoring programs?

(TMO note: To be clear, Birdie is not a game app; it is an app designed for real golfers to enter and save their scores)

Rensch: Oh yes. There are 4 or 5 competing programs on the same level. They all have a similar cost. Birdie sells for $18.99.

TMO: Wow! That's pretty expensive for an iPhone app. Are you concerned that the price may hurt sales?

Rensch: Not really. The cost is much less than a single day's greens fee. Golfers appear to consider it a bargain.

TMO: Moving on, tell me a bit about TwittMS. Why would I want an application just for direct messages when I already have several Twitter clients that do direct messaging and everything else?

Rensch: Yes, you can do direct messaging with other apps, but it's usually a pain. Often, you have to manually enter the person's name to send a message. Plus, messages sent and messages received are usually stored in two different locations, so you can't easily follow a conversation.

TwittMS allows you to set up a group of direct message Favorites, selected from all your followers. You can easily send them a message without having to deal with the rest of the Twitter interface. Next, it maintains all the messages between you and each user as a continuing iChat-like conversation.

(TMO note: I briefly tried out the app and can confirm it is as simple and effective as it sounds. Plus, the graphics and user interface are very slick. Definitely worth checking out!)

TMO: Will you be updating your apps for iPhone 3.0?

Rensch: Most definitely. Updates are already pretty much done and ready to go when 3.0 launches. The update for TwittMS will add push notifications, so you will get an alert whenever a new direct message comes in, even if you are not running the app. Birdie will take advantage of the new 3.0 option to send attachments via email from other apps; you'll be able to send score sheets to others.

There's no doubt that iPhone OS 3.0 is an important update, with many great new features.

TMO: How is it to deal with the App Store for selling your apps?

Rensch: It's very good overall. I would still use the Store even if there were other options, such as direct downloads from the Web. Because only from the App Store can you download and install an app directly from the iPhone itself. This is a great convenience.

Still, there are some notable problems with the App Store.

It's irritating that, when you get negative reviews from users, there is no way to respond to them.

Also, unless your program is very popular, and gets in the "Top" lists, they tend to sink into the noise. It's very hard for a new program to get noticed. I'm not sure there is much Apple can do about this. But it is a problem. Perhaps they could have better search tools, so users could find a given app more easily.

Most annoying is that your program can get rejected by Apple and never make it to the App Store, often with no clear reason as to why. This can be especially a problem if someone hires you to write an iPhone app. This happened to me once. Before I began, I had to explain that, after I finished the app, I could not guarantee that it would ever appear in the App Store. And there is no way I can find out before submitting the program what Apple's decision may be. It was hard for the company to understand this.

TMO: So it is worth coming all the way from Germany to attend the WWDC?

Rensch: Yes. This is my fourth time coming. It is definitely worth it.

TMO: Thanks for spending time with us. Enjoy the rest of the WWDC.