Lording it over competitors BlackBerry and Nokia – both still in the formative stages of launching online stores – Apple has set up an online ticker so the world can watch its one billionth AppStore download approach. But there is at least one fly in the ointment.

By most measures, AppStore is booming.

Since its launch in June last year, the online store has enjoyed accelerating success, with around 500 million of its near-billion downloads being sucked down onto iPhones and iPod Touches in the past four months alone.

AppStore has re-written the rules of the cellphone software market, previously tightly controlled by telephone companies. Suddenly, customers have become acclimatised to a pick-and-mix, download your own programmes approach that puts them in control.

Google, with Android and now BlackBerry with AppWorld and Nokia with its pending Ovi, have followed suit.

However, Apple refuses to say how many of AppStore’s downloads are paid, and how many are free, or to break out the store’s result (reported under iTunes fast-growing revenue).

BlackBerry, with its just-launched AppWorld, has chosen to price its programmes higher, and go for a more business-oriented approach (themes and wallpapers for example, are banned from its store).

The Top 20 lists of paid and free AppStore lists posted on Apple’s ticker site today indicate that mostly frivolous, cheaper-priced faire dominated its downloads. (The number one free app: Facebook. Heading the pay chart: the $2.59 Crash Bandicoot Nitro, heading off iBeer - also $2.59 - a visual gag app that makes a beer animation on your iPhone’s screen tip along with your phone.)

But there’s also no doubt that however much money it makes - or doesn’t - AppStore has been a key reason for persuading millions of people to buy or upgrade an iPhone. For Apple, it’s all good.