Writing showmessage promt to a log

Hello,

I am modyfiying a vbs script and there is a line that comes in the script that says script is completed.  It is because of the code below in the script:

'Notify user script completed
ShowMessage ("Script Completed" & vbCRLF & vbCRLF & "All activities of this script have been logged to " & sLogFile)

I know I can take out these lines to avoid the prompt, however what I want to do is instead of showing message on the screen, I want to write the same message to the log file which is sLogFile I believe.  Can someone help?

Adam