Write the date when you sign the application.
My wife opened a pizza place December 2010 which is still open until this point.
I am applying for the Visitor Visa and on page 3 of the form "Application for temporary resident visa made outside of Canada" there is a section called "Current Occupation Give full details of your present job."
Now when they ask when it began "From" there is no problem but they are also asking "To" now that means when it the job or business ends?. The business is still running as I mentioned above, so if I put February 2011 the officer will think the business closed at that date. I asked the Canadian embassy to ask if I can put "Present" on the part where it says "To" but they said It wouldn't be recommended. Is there someone who knows what I can type on that place???