Windows Phone 7 is still pretty young compared to most of its competitors in the mobile space, but when it comes to the number of applications available, Microsoft's OS is already doing pretty well for itself.  According to unofficial app tracker WP7applist, there are now over 4,000 apps available in the Windows Phone 7 Marketplace.  As of this writing, the site says that its following 4,162 apps available.  If you're interested in some statistics, WP7applist has them in spades: 29 percent of apps are free, average selling price of a paid app is $1.41, and there were 80 apps added to the Marketplace in the last day.

While 4,000 apps may not sound that impressive compared to Android's 100,000 and Apple's 300,000, it certainly seems like Windows Phone 7 is doing pretty well for itself in the world of apps.  Perhaps luring developers with cash and devices will end up paying off for Microsoft.  Of course, we all know that quality of apps is just as important as quantity, so now I ask you this: which quality Windows Phone 7 apps have you all been using?

Via BGR, WP7applist