I am going to start things off easy. Here is a script I created that will automatically lock a workstation. If you do not know how to create a VBS script, stay tuned. I will post a basic tutorial on creating VBS scripts. Anyway, here is the script; start your copy at 'VBSBOB:
On Error Resume Next
Set objShell = CreateObject("Wscript.Shell")
objShell.Run "%windir%\System32\rundll32.exe user32.dll,LockWorkStation"