Converting primary to rental - timing for tax deductions

[Dan Gingrich]

We're planning on buying a new house and converting current house into a rental.  This will be our first rental property.  Current house will need new carpets, baseboards, some painting, etc before renting.  I believe this stuff would be tax deductible on a rental so it seems smarter to wait until the house becomes a rental before doing this work.  When does the house officially get labeled a rental for tax purposes?   What would be the best timing for doing these improvements?