With competitors trying to set up similar services in droves, it seems that Apple’s App Store is becoming unassailable, hitting 2 billion downloads since its launch this week.

It’s important to keep in mind that the announcement that the App Store has shifted as many apps as it has comes just 14 months after its launch in July of last year. Moreover, the most recent announcement with any hard figures for the App Store came in almost exactly at the App Store’s first birthday, informing the world and sundry that Apple had crossed the 1.5 billion download mark. That means that, in the two months since then, iPhone and iPod Touch users have downloaded another half a billion apps, which is no small feat.

While there are a significant number of free apps available from the App Store, it’s clear that a pronounced proportion of the 2 billions apps downloaded will have been feeding money to both Apple and developers, though Apple is being characteristically tight-lipped about just how much profit it’s seen from the App Store itself.

It’s also worth noting that Apple’s chief, Steve Jobs, has said that the iPod Touch is being seen more and more as not only a portable media player, but a window into the App Store for those unwilling to commit to the iPhone for one reason or another. Clearly Apple is managing something of a runaway success with the App Store, regardless of the negative attention its attracted for the blocking of apps that seem to be particularly Apple-unfriendly.

Regardless, this is an announcement that shows that you can flirt with controversy for months on end and still run a scarily successful service with those apps that make it to the store itself. Now that Palm has its App Catalog up and running it’ll be interesting to see how the figures stack up, if only in terms of number of apps downloaded per capita.