Yes, the stocks that are added to the S&P 500 (or for that matter the S&P 600 Small Cap, S&P 400 Mid Cap) or any of the Russell indices do rise after immeditately addition. Typically around 1 to 3% (this is my personal observation, not a statistical measurement). Conversely, stocks that are removed from the indices, or stocks that are downgraded (such as moving from the Mid Cap to the Small Cap index) do fall in price.
The problem with trying to take advantage the S&P index changes is that I don't believe that the schedule is pre-announced, so there is no way to predict which stocks to buy/sell, or when. The announcements are simply made after market close. Also, the S&P indices, such as the S&P 500, don't always have an exact number of stocks, due to spinoffs or mergers. Right now the S&P 500 has 505 stocks. So you wouldn't know exactly how many stocks will be added or deleted.
The Russell index changes on the other hand are very playable. The change schedule is once per year, immediately after market close, and is announced months in advanced. Usually there are several stocks eligible, and the final selections are strictly based on Market Cap, using the closing price on the evening of the changes.