I'm trying to program a .NET Windows Application which has an editable
combobox in a datagrid. I'm struggling with getting the combox to show
in the datagrid and be editable. Does anyone have experience with .NET
Datagrids and comboboxes that can answer some questions or help me get
this to work?  This will require a few questions back and forth, so
we'll need to communicate via email, IM or phone.

Try the following link:
http://www.rustemsoft.com/DataGridColumns.htm
DataGridColumns .NET assembly is a DataGrid Columns Styles software
package specifically designed for .NET Forms developers.

Hi
You can write a Class that inherits.. "DataGridBoolColumn".
Override all the required Values..for the inherited class..  in the constructor.
Code goes something like this...

Public Class CGridCheckBoxStyle
   Inherits DataGridBoolColumn

      Public Sub New(ByVal MappingName As String)
         MyBase.New()
         Me.MappingName = MappingName
      End Sub

      Public Sub New(ByVal MappingName As String, _
                     ByVal Width As Integer, _
                     ByVal Alignment As HorizontalAlignment, _
                     ByVal [ReadOnly] As Boolean, _
                     ByVal HeaderText As String, _
                     ByVal NullText As String, _
                     ByVal FalseValue As Object, _
                     ByVal TrueValue As Object, _
                     ByVal AllowNull As Boolean, _
                     ByVal NullValue As Object)
         Me.New(MappingName)
         Me.Alignment = Alignment
         Me.Width = Width
         Me.ReadOnly = [ReadOnly]
         Me.HeaderText = HeaderText
         Me.FalseValue = FalseValue
         Me.TrueValue = TrueValue
         Me.NullText = NullText
         Me.NullValue = NullValue
         Me.AllowNull = AllowNull
      End Sub
   End Class


And use this class in the main class where u want to show the grid...
like this..

After filling the DataAdapter..
         dataAdapter.Fill(dt)

      'Create a TableStyle to which ColumnStyles will be added
        Dim ts As DataGridTableStyle 

        ts.GridColumnStyles.Clear()
        ts.MappingName = dt.TableName

      'CheckBox Column
        Dim cs1 As New CGridCheckBoxStyle("Column1", 60, _
                                        HorizontalAlignment.Center, False, _
                                        "Select", "", False, True, False, False)
        ts.GridColumnStyles.Add(col)

This will Add CheckBoxes to a Bound Datagrid.

Hope it is clear

Regards
Packiyanath.