German mobile games publisher Fishlabs has announced plans to take its Rally Master Pro mobile game to iPhone and iPod touch this Autumn.

The original won widespread acclaim for its 3D graphics, which Fishlabs says are being beefed up for the capabilities of Apple's devices. Particle physics and dynamic lighting are two of the key improvements that take advantage of iPhone's graphics acceleration hardware.

However, the mobile version of Rally Master Pro also won praise for its inventive business model, where the core game was released for free, with players paying to download additional tracks.

Despite in-app payments being one of the features of the iPhone 3.0 software, Fishlabs boss Michael Schade tells ME that the downloadable content won't be part of iPhone Rally Master Pro when it launches.

"It would be too much work implementing this in Rally Master Pro, and also from the OS 3.0 stats of our Waterslide Extreme game, we would lose 40% of potential customers," says Schade.

"Of course, we are excited about in-app purchases, and would love to monetise at a reasonable price point and with additional content over time. There's no reason not to come up with more rallies and features within Rally Master Pro when the percentage of OS 3.0 users is about 80%."

Schade thinks that milestone might be reached after Christmas this year, when millions more iPhones and iPod touches have shipped with the 3.0 software already installed.