[Source: http://geekswithblogs.net/EltonStoneman]
23 months after the original post on Generating Deterministic GUIDs, I still find myself doing it fairly often and still using the same code (MD5 may not be suitable for secure scenarios, but it's fine for generating GUIDs for normal development use).
This post contains a Silverlight widget which generates GUIDs for you on the fly:
Hit GUID to get a random GUID (from a call to Guid.NewGuid()), or enter text in the box to generate a GUID from the MD5 hash of its contents. It'll ask you for permission to use your clipboard, and if you agree the GUID it generates will be pasted into the clipboard.
The code (VS 2010) is on github here: Silverlight Guid Generator.
Not much to it, only noteworthy point is that Silverlight doesn't have a native MD5 provider, but there's an implementation of the algorithm on MSDN Code Gallery – Silverlight MD5 – which is correct and produces the same hash as the provider in the full .NET framework.