Is it "two weeks' notice" or "two weeks notice"?

This came up recently. Is it "two weeks' notice" or "two weeks notice"?

According to the University of South Australia site the apostrophe is included, but according to the Australian Government's style guide it isn't included.

I consider this to be the situation where our language is evolving and the apostrophe is no longer needed. Interestingly Microsoft's grammar checker suggests the apostrophe should be included. If the language has evolved then the suggestion by Microsoft's grammar checker is now wrong and misleading people. I've seen quite a few examples of where the spellcheckers suggest incorrect words so this isn't a total surprise.

What do you think?

Kelvin Eldridge
www.Australian-Dictionary.com.au

President Obama misspells respect. Notice the laughter from the audience.

We all make mistakes when spelling, even the president of the United States of America. In referring to Aretha Franklin's famous song, President Obama spelt respect as RSPECT. If you think people don't notice incorrect spelling, perhaps think again. The audience laughs at the fumble by the president. In this case the people are laughing at the president and not with the president.

You can view the video here.

Kelvin Eldridge
www.Australian-Dictionary.com.au