Disposing objects in .net

Hi all,
  What is the best practice on disposing objects in a .net method?  I tend to avoid try/catch blocks as much as possible, so lets say I have a method in vb.net code behind that instantiates an object (The object may be  a local variable or a class variable).
Should I call objectName.dispose() when I am done with it?
 I am keeping in mind that I should aquire the object late and release it early during that method execution.
code looks like this:
 Private Sub Entity_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
        Dim db As New LinqDataAccess.QuantumDataContext
        Dim result = db.GetAddressType("Company")
      '''''Dispose it
       db.dispose()
...