The move follows more than two years of complaints from software developers about the company's secret and seemingly capricious rules, which block some programs from the store.
Developers have had little guidance from Apple, meaning they often had to complete their programs only to find them blocked by the company. The company has been known to block applications because of sexual content, because they contain political satire, and because they just don't do much.
All the same, Apple's store has been a runaway success since its launch in 2008, and now has more than 250,000 applications for iPhones, iPads and iPod touches.
Apple also said it will lift restrictions imposed earlier this year on using third-party development tools that "translate" code written for another platform. That means developers who work in Adobe Systems Inc.'s Flash or Oracle Corp.'s Java language can convert their programs into iPhone apps without rewriting them.
The App Store's chief competitor, Google Inc.'s Android Marketplace, has few restrictions for developers.
Adobe shares jumped on the news, rising $2.29, or nearly 8 percent, to $31.60 in morning trading. Apple shares rose $2.87, or 1.1 percent, to $265.79. Google shares gained $8.68, or 1.8 percent, to $479.26. Oracle shares rose 23 cents to $24.37.