Is there any LGPL or commercial-friendly licensed implementation of Jaro-Winkler distance in .NET?
The SimMetrics library appears to support Jaro-Winkler, and there's a .NET version available for download.
Unfortunately it's licensed under the GPL, but maybe the authors would be amenable to giving/selling you a commercial license.
(NB: I haven't used this library myself, and know absolutely nothing about it.)