Microsoft is offering 90-day evaluation of Windows 8 Enterprise edition (32 and 64-bit versions in a varied languages) can be had for free at the Windows Dev Center developer downloads page right now. Before you get cracking on apps for Microsoft’s new OS, however, you’ll need to grab the newly released Visual Studio 2012 as well. The Express version which allows for Metro Windows 8-style apps only is free, while the full Visual Studio experience is only currently available to MSDN subs. Additionally, the folks in Redmond have made it easier to write those apps by releasing the new .NET Framework 4.5 RTM.

Windows 8 Enterprise includes all the features of Windows 8 Pro and more business-focused options like Windows To Go — a new way to run a Windows 8 installation from a USB key. If you’re simply looking to test out Windows 8 before it’s available in stores then the trial version is a safe bet, but be warned you’ll need to reinstall the operating system once Windows 8 and Windows 8 Pro become generally available on October 26th.