Software developers have downloaded the iPhone software development kit (SDK) 100,000 times since it was made available last week. “Developer reaction to the iPhone SDK has been incredible,” said Philp Schiller, Apple’s senior vice president of worldwide product marketing.

Schiller said a million people watched the video of last week’s SDK launch, which demonstrates the interest developers have in creating applications for the iPhone.

“We’re excited that the iPhone expands the ways our customers can solve key financial tasks wherever they might be,” said Rick Jensen, a senior vice president at Intuit.

NetSuite Vice President Luke Braud said his company is “excited at the opportunity to give every iPhone customer access to their critical business data anytime, anywhere.”

Ethan Einhorn, who demonstrated a version of Super Monkey Ball at the launch, told the San Francisco Chronicle that he was surprised at the iPhone’s graphic power. “The thing that was very exciting for us was we could make something closer to a console experience in a mobile game,” he said.

Not all developers are happy with the SKD. Third-party applications can’t run in the background which means they can’t multitask. Apple written application can run in the background.

“The Apple SDK, as many have come to find, has arguably crippled much of the functionality that set the iPhone apart when first released. Even simple features like the ability to run a program in the background have been crippled in the Apple SDK,” reported Jonathan “NerveGas” Zdziarski, author of the book iPhone Open Application Development.
Developer reactions are “somewhat mixed,” said Greg Sterling, principal analyst with Sterling Market Research, in a telephone interview. “There’s a lot of enthusiasm and demand. There’s also some criticism and concern.”

Sterling expects Apple will take corrective measures. “I imagine Apple will try to remedy the most heavily criticized aspects of the SDK,” he said. “I would expect them to be responsive, given that the SDK itself is a response and they’re trying to strike a balance between security and access.”