Microsoft today opened up its Windows Marketplace for Mobile to developers. The move, which brings Windows mobile up to date with Apple's App Store and the Android Market, provides developers yet another way to generate revenue from their applications.

According to Microsoft, the process is simple. You'll need a Live ID and $99 to sign up; to get paid, you'll need to provide bank account and tax identification details.

The Marketplace is designed for Windows phones running Windows Mobile 6.5, which are expected to go on sale sometime in September 2009, and as pointed out by Microsoft last month, developers will receive 70 percent of the revenue from the sales of each application. Developers will also have the ability to set the pricing for their apps.

Important to note, however, is the annual registration fee of $99 only allows you to put forward up to five submissions per registered year; additional submissions will cost $99. If you're a student developer, the registration fee will be waived if you enroll in Microsoft's DreamSpark program.

Although Windows Mobile only has a 5.98 per cent market share, Microsoft claims that more than 20 million smartphones were sold in 2008 that had its software on board. Given the Marketplace will be placed on every Windows phone, this is not an insignificant number, and one that may provide developers with the opportunity to earn a considerable amount of money.

More information can be found here.