from arstechnica.com

Today Vista launches. I’ve received a number of e-mails from readers looking for more information on the black arts of the OEM edition, so here it is: my brief introduction to everything you need to know before going OEM.
What is OEM?

OEM stands for Original Equipment Manufacturer, and most often refers to the likes of Dell or Gateway. At least originally, “OEM versions” of products were usually the same products that you’d find at retail, but with no-frills packaging, reduced support, and sometimes lesser warranties.

When it comes to Windows, “OEM editions” most often refer to the cheaper versions of Windows made available to “system builders” and other classes of Microsoft partners. You can buy OEM versions of Windows online almost any place that sells software, such as NewEgg. Companies keep compliant with Microsoft’s rules by bundling OEM versions with a token piece of hardware, like a cable. Here’s a glimpse of current OEM pricing:

* Vista Home Basic $99 (full version retail: $199)
* Vista Home Premium: $119 (full version retail: $239)
* Vista Business: $149 (full version retail: $299)
* Vista Ultimate $199 (full version retail: $399)