Getting VIX Options Historical Data
VIX options historical data is available through the CBOE DataShop (previously Market Data Express), which you can find listed on CBOE website (under "Data" in the main menu).
If you only need VIX options data, you can order the VIX symbol only (otherwise you can order data for all CBOE option contracts, which may be unnecessarily expensive in total, but of course much cheaper per symbol).
VIX Options Historical Data for Free
At present I don't know of any free sources of VIX options historical data with good quality and convenient format. You can get some VIX options history from some retail brokers (for example using the thinkBack feature with ThinkOrSwim). Nevertheless, if you want a reliable systematic solution, you will probably have to pay for the data.
Yahoo Finance VIX Options Data
You can find current (several minutes delayed) option quotes on many financial websites. Yahoo Finance has been a popular source for free data. You can't download historical option prices from Yahoo, but if you only need a short recent period, you can download VIX option quotes from Yahoo at the end of each day.