With an official launch expected some time this winter, Microsoft is using its web design and developers conference MIX in Las Vegas to push Windows Phone 7 - the firm today announcing the launch of the OS's official developer tools.

It's available for free, and studios can now pick it up from the platform's developer website.

XNA lead program manager Michael Klucher has already revealed that the download comes with Visual Studio 2010 Express, Windows Phone 7 Series add-ins for Visual Studio, a Series 7 OS emulator and XNA Game Studio 4.0

MIX10 has also marked the official release of UI design tool Expression Blend 4 for the platform, group director of program management Christian Schormann stating on his blog that a beta version is already available for download on Microsoft's website.

"You can create applications for Windows Phone 7 Series in Blend 4, and it feels just like making Silverlight apps," says Schormann.

"I am of course not objective, but I think Blend 4 is one of the coolest ways to design and create apps for any phone around."

You can watch live streams of the event by visiting Microsoft's official MIX10 website.