With Facebook’s rapid growth around the world, more and more of its new users have been accessing the site through their mobile phones . And mostly not through the iPhone, but rather through the devices made by Nokia, Samsung and others — the devices that dominate much of the world. A company called GetJar has been making it easier for these mobile Facebook users to find mobile apps designed to operate natively on their device of choice, with some impressive results.

Over the past couple of months, Facebook has been using GetJar’s new “App Download Page” service to automatically alert users about native mobile apps whenever they try to access Facebook through the mobile web. Around 8.5 million app downloads since the the service launched with Facebook, or around one million downloads a week, the companies say today. Other companies, like Google, have built this sort of service themselves, but GetJar has managed to sign up not just Facebook but also PhotoBucket. More on how it works, from mocoNews:

The service provides developers with a mobile web page, which can be linked to from any site. The site detects what device a user has, and then offers a link to download the application. If GetJar doesn’t have a version for the user’s specific handset, it provides a free widget that will launch the site from the phone’s web browser.

Facebook has been working with, at last count, around 180 carriers around the world to integrate various types of mobile applications in with their offerings. Some 65 million people among its 300 million monthly active users are now accessing the site through their phones every month — as around 70 percent of Facebook users are now outside of the US, we can assume that a large portion of its users are international, and mobile.

Meanwhile, we’ve been tracking the growth of Facebook’s own mobile web app: It has grown from seven million monthly active users three months ago to 12.3 million monthly actives today, according to AppData. That growth seems to be increasing, despite GetJar’s service actively directing many of these users to download native apps instead.

So, while Facebook’s iPhone app continues to be the single most popular mobile app, having grown quickly to nearly 15 million monthly active users today, GetJar appears to be spurring growth in the “long tail” of the mobile app world. We don’t have data on all of these apps, although larger ones include Facebook for Blackberry, which has 9.64 million monthly active users. Other mobile apps include those for phones from INQ, HTC, LG Electronics, Motorola, Palm, RIM, Samsung and Sony Ericsson, the T-Mobile Sidekick, and phones powered by Microsoft’s Windows Mobile. Facebook has also rolled out an SMS service where users can update their status and receive notifications, and it’s available in 52 operators in 25 countries.