' Create an Icon in System Tray Needs
Public Type NOTIFYICONDATA
cbSize As Long
hwnd As Long
uId As Long
uFlags As Long
uCallBackMessage As Long
hIcon As Long
szTip As String * 64
End Type
Public Const NIM_ADD = &H0
Public Const NIM_MODIFY = &H1
Public Const NIM_DELETE = &H2
Public Const WM_MOUSEMOVE = &H200
Public Const NIF_MESSAGE = &H1
Public Const NIF_ICON = &H2
Public Const NIF_TIP = &H4
Public Const WM_LBUTTONDBLCLK = &H203 'Double-click
Public Const WM_LBUTTONDOWN = &H201 'Button down
Public Const WM_LBUTTONUP = &H202 'Button up
Public Const WM_RBUTTONDBLCLK = &H206 'Double-click
Public Const WM_RBUTTONDOWN = &H204 'Button down
Public Const WM_RBUTTONUP = &H205 'Button up

Public Declare Function Shell_NotifyIcon Lib "shell32" Alias "Shell_NotifyIconA" (ByVal dwMessage As Long, pnid As NOTIFYICONDATA) As Boolean

Code:
Dim nid As NOTIFYICONDATA ' trayicon variable

'----------------------
'--- command1 click ---
'----------------------
Private Sub Command1_Click()
minimize_to_tray
End Sub

'------------------------
'--- create tray icon ---
'------------------------
Sub minimize_to_tray()
Me.Hide
nid.cbSize = Len(nid)
nid.hwnd = Me.hwnd
nid.uId = vbNull
nid.uFlags = NIF_ICON Or NIF_TIP Or NIF_MESSAGE
nid.uCallBackMessage = WM_MOUSEMOVE
nid.hIcon = Me.Icon ' the icon will be your Form1 project icon
nid.szTip = "blablabla text u want to show when mouse over tray iicon" & vbNullChar
Shell_NotifyIcon NIM_ADD, nid
End Sub

'---------------------------------------------------
'-- Tray icon actions when mouse click on it, etc --
'---------------------------------------------------
Private Sub Form_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
Dim msg As Long
Dim sFilter As String
msg = x / Screen.TwipsPerPixelX
Select Case msg
Case WM_LBUTTONDOWN
Me.Show ' show form
Shell_NotifyIcon NIM_DELETE, nid ' del tray icon
Case WM_LBUTTONUP
Case WM_LBUTTONDBLCLK
Case WM_RBUTTONDOWN
Case WM_RBUTTONUP
Me.Show
Shell_NotifyIcon NIM_DELETE, nid
Case WM_RBUTTONDBLCLK
End Select
End Sub

'------------------------------
'--- form Actions On unload ---
'------------------------------
Private Sub Form_Unload(Cancel As Integer)
Shell_NotifyIcon NIM_DELETE, nid ' del tray icon
end Sub