Well for those who are interested:

Grok's WriteLog in VB .NET

[code]
Imports System
Imports System.IO


Public Sub WriteLog(ByVal Text As String)
Try
Dim FileHolder As FileInfo _
= New FileInfo(Date.Now.Year & Date.Now.Month & Date.Now.Day & ".txt")
Text = Text.Insert(0, "[" & Format(Date.Now.Hour, "00") _
& ":" & Format(Date.Now.Minute, "00") _
& ":" & Format(Date.Now.Second, "00") _
& ":" & Format(Date.Now.Millisecond, "0000") & "] ")
If FileHolder.Exists Then
Dim WriteFile As StreamWriter = FileHolder.AppendText()
WriteFile.WriteLine(Text)
WriteFile.Close()
Else
Dim WriteFile As StreamWriter = FileHolder.CreateText()
WriteFile.WriteLine(Text)
WriteFile.Close()
End If
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
[/code]

Usage - not that hard ;)
[code]
WriteLog("Well i really want to log now something :-)")
[/code]