Hacker News Reader

Short: http://a-little-book-of-r-for-time-series.readthedocs.org/en... or http://people.duke.edu/~rnau/411arim.htm

And for a longer, a book by the author of R forecast library: https://www.otexts.org/fpp/

This book is extremely practical - I would definitely recommend it for doing actual time series analysis. That said, it's not a learn time series book. It's a do basic time series in R book.

Hyndman's online forecasting book https://www.otexts.org/fpp has an ARIMA section that covers pretty much everything a practitioner would need.

Try one of the forecasting books on Frank Diebold's page: http://www.ssc.upenn.edu/~fdiebold/Textbooks.html

I use the Elements of Forecasting book in an undergrad forecasting class that I teach. Forecasting will be better, but I'm not sure if it's completed.