Even though Microsoft’s iPhone-fighter isn’t yet on sale, Microsoft  boasts that over 300,000 developers have downloaded their Windows Phone Developer Tools. The company has also released a 12-section interactive training course for Windows Phone developers.

To catch up with the competition, Microsoft is going to need the help. In June 2010, Apple boasted that there were more than 225,000 iPhone apps available, up from 120,000 at the beginning of the year. Last month, Google claimed that the Android marketplace had over 100,000 apps available, with 10,000 new ones added every month. (The Windows Phone 7 applications marketplace isn’t scheduled to open until October 2010, so no comparable statistics are available for it yet.)

One thing is certain: Microsoft is putting far more energy into recruiting and training Windows Phone 7 developers than it put into helping outside developers work with its earlier Kin smartphone operating system, which proved, in the end, to be a failure in the marketplace.

Exact numbers of unit sales, developers and applications aside, it is obvious that Apple had a huge head start in the smart phone marketplace. Android came from behind and is now either rapidly catching up to the iPhone or has already surpassed it, depending on whose numbers are consulted.

But, historically, Microsoft has managed to enter more than one market well behind competitors and dominate it within a few years (Internet Explorer), or at least become a credible competitor (the Xbox 360).

The Windows Phone Developer Tools are free, and Microsoft is putting big money behind the Windows Phone 7 launch, with an added marketing push over the associated Applications Marketplace.