You are probably meaning lambda expressions and LINQ?
http://blogs.msdn.com/vbteam/archive/2007/09/11/lambda-expressions-and-expressio
n-trees.aspx

Here's an example

Public Class MySampleClass

   Public Sub New(ByVal Name As String, ByVal City As String)
       Me.Name = Name
       Me.City = City
   End Sub

   Private _name As String
   Private _city As String

   Public Property Name() As String
       Get
           Return _name
       End Get
       Set(ByVal value As String)
           _name = value
       End Set
   End Property

   Public Property City() As String
       Get
           Return _city
       End Get
       Set(ByVal value As String)
           _city = value
       End Set
   End Property

End Class

Dim l As New List(Of MySampleClass)
       l.Add(New MySampleClass("Karl", "NY"))
       l.Add(New MySampleClass("Mike", "NY"))
       l.Add(New MySampleClass("Lars", "LA"))

       Dim lookingFor As String = "NY"

       Dim guys = From person In l _
                  Where person.City = lookingFor _
                   Select person

       For Each p As MySampleClass In guys
           Response.Write(p.Name)
       Next