While many sites are reporting that the iPhone App Store has hit 10,000, MacRumors says it's not quite there yet, but will be soon:
While several sites have reported that 10,000 iPhone Apps have been released into the App Store, the actual number of active iPhone apps that can be downloaded is about 9,676 as of today's count. The discrepancy comes from the fact that many apps have been removed from the App Store for various reasons (trademark infringement, discontinued apps, pulled and released).
With approximately a quarter of those being games, and a tenth each for entertainment and utilities.
Want to get your App up as part of the next 10,000? Erica Sadun has some tips for you. What are they in brief?
Keep your icon consistent throughout the various sizes, don't link to web sites you haven't deployed yet, don't ever include any mention of "beta", and do not reference forbidden accessories (like a mic for the iPod Touch).
Check out the full article on App Store Lessons for much more by way of explanation and example.