Download the npgsql 1.01 driver from pgfoundary -
For ASP.NET 2.0 you'll want - Npgsql1.0.1-bin-ms2.0.zip and for Mono.NET you'll want Npgsql1.0.1-bin-mono-2.0.zip. Unzip and place the files in bin folder of your web app project.
Since we are just creating a simple REST web service and don't need any plumming of the standard SOAP like webservice, we will be using
a .NET handler class (ashx) instead of an asmx. We have two versions listed below. One for C# and one for VB.NET/Mono Basic