Redmond-based Microsoft has opened the gates of its Windows Marketplace for Mobile for software developers that would like to make their applications available to Windows Mobile phone users through the new app portal, set for launch at the same time with the 6.5 iteration of the mobile operating system.

Those who would like to add their apps to the Windows Marketplace for Mobile will need to own a Windows Live ID, a valid taxpayer ID and a credit card with $99 on it, sign an application provider agreement and create a profile. One thing that should be noted is that the applications will only be developed for Windows Mobile 6.5, as the store will only be available for access on phones featuring this OS, which are expected to come to the market sometime in September this year. Future iterations of the platform will also support the portal.

Another important thing is that each application submitted to the Marketplace will be reviewed and approved in accordance with Microsoft’s application submission guidelines. At the same time, those developers willing to access the app store now to submit software solutions will have to use Internet Explorer to do so, as it seems that “some issues with non-Microsoft browsers” have been noticed.

As many of you might already know, Microsoft has set a $99 annual fee for Windows Mobile application developers, yet it has also limited the number of submitted applications to 5. While updates for the already submitted apps do not count here, the cost for adding more software to the marketplace is of $99 for each new app.

For what it's worth, it seems that Microsoft is finally determined to show the world that it is highly interested in what happens on the mobile side of its business. Not only the Marketplace shows it, but all the features that are expected to come with Windows Mobile 6.5 are also meant to prove this. Once the platform is here and the app store is up and running, we should be able to learn more on all the goodies the company has in store for us. More info can be found here.