Sounds like dhowser wants to use a list of email addresses in an excel sheet to form an email group.
Try the following code:
Private Declare Function ShellExecute Lib "shell32.dll" _
Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, _
ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, _
ByVal nShowCmd As Long) As Long
Sub SendEmail()
Dim URL As String, Email As String
Email = Worksheets("Sheet1").Range("a1") & ";" & Worksheets("Sheet1").Range("a2")
URL = "mailto:" & Email & "?subject=" & "Insert Subject" & "&body=" & "Insert Message"
ShellExecute 0&, vbNullString, URL, vbNullString, vbNullString, vbNormalFocus
Application.Wait (Now + TimeValue("0:00:01"))
Application.SendKeys "%s"
End Sub
Edit it to fit your needs.