Apple’s CEO Steve Jobs has struck out at rival app store offerings from RIM, Google and Nokia while confirming its own service now boasts 300,000 apps.

Taking aim at RIM, Jobs noted on the firm’s quarterly conference call last night that “they must move beyond their area of strength and comfort, into the unfamiliar territory of trying to become a software platform company… I think it’s going to be a challenge for them to create a competitive platform and to convince developers to create apps for yet a third software platform after iOS and Android.” Jobs’ comments come after RIM last month said that BlackBerry App World users are downloading more than 1.5 million apps per day on average and that the store has hit the 10,000 apps milestone and is now available in 65 markets with support for six languages. The company is also embarking on a major charm offensive with developers, attempting to lure them into supporting BlackBerry App World with a number of new tools and services.

Turning his attention to Android, Jobs then said: “Last week, Eric Schmidt reiterated that they are activating 200,000 Android devices per day, and have around 90,000 apps in their app store. For comparison, Apple has activated around 275,000 iOS devices per day on average for the past 30 days, with a peak of almost 300,000 iOS devices per day on a few of those days. And Apple has 300,000 apps on its App Store.”

Highlighting the fragmentation issues around Android, he went on to state that “Many Android apps work only on selected Android handsets, running selected Android versions. And this is for handsets that have been shipped less than twelve months ago! Compare this with iPhone, where there are two versions of the software, the current and the most recent predecessor, to test against.” He cited one app developer who said it had to deal with more than 100 different versions of Android software on 244 different handsets. Jobs also noted that the recent emergence of online stores for Android applications would force developers to work much harder to distribute their apps than they do with Apple’s single, supervised store for iPhone and iPad programs.

With a dig at the fact that some versions of the Android operating system are not optimised for use on tablets, and therefore the Android Market app experience is not always perfect on tablets, Jobs noted that the iPad now supports over 35,000 apps from Apple’s App Store. The introduction of new 7-inch tablets (from the likes of Samsung and RIM) “will have near zero,” he claimed, and the smaller screen size would not provide a good user experience with apps.

Finally, Jobs wasn’t about to let Nokia off the hook either: “Nokia makes US$50 handsets, and we don’t know how to make a great smartphone for US$50. We’re not smart enough to have figured that one out yet, but believe me I’ll let you know when we do… Most of them [developers] will not follow you. Most of them will say, ‘I’m sorry, but I’m not going to write down a watered-down version of my app just because you’ve got this phone that you can sell for US$50 less, and you’re begging me to write software for it’.”