Microsoft released Windows Phone 7.1 SDK tools yesterday, 28th September 2011. It’s in RTW release, that means, it is released to web. Cliff Simpkins announced the release of the Windows Phone SDK 7.1 in Windows Team Blog.
In this post, find the link to download the RTW version of Windows Phone 7.1 SDK (Mango) which includes both the web and standalone offline installer for all separate languages.