Let me introduce you to my latest CodePlex Project

GrapheNet

GrapheNet is a graph Library for .Net

Currently the dll is about 25Kb

Example

Imports GrapheNet.Graph

Module Module1

  Sub Main()
    Dim a As New Graph(Of String, Integer)(directed:=True,
                                           allowsReflexivity:=False)
    a.AddNode("A")
    a.AddNode("B")
    a.AddNode("C")
    a.AddNode("D")
    a.AddNode("E")
    a.AddEdge("A", "E", 2)
    a.AddEdge("E", "B", 3)

    Dim q = a.GetPaths("A", "B")
    Console.WriteLine(q(0))
  End Sub

End Module

Download GrapheNet and use it in your projects.