Okay I will have a class that will have 2 threads sent to it. My question is what will be the best way for those threads to access a function that accesses 2 of my controls(listbox and a trackbar) that is in my form1 class without crossthreading?

Ex:(form1.vb)

public function INeedToAccessThis() as string
'do stuff with listbox
'do stuff with trackbar
return infoneeded
end function

ex: Class1

public sub ThreadProc()
'need to call form1.INeedToAccessThis
end sub

All Controls implement the ISynchronizeInvoke interface.  Where you need to call ThreadProc, you might code:
[code]
If Form1.InvokeRequired Then
    Form1.Invoke(AddressOf ThreadProc)
Else
    ThreadProc()
End If
[/code]

Thank you