One of the best tools for indoor cycling training is to use a powermeter. It has helped me immensely. Most powermeters cost hundreds to thousands of dollars but you can build a  "virtual powermeter" using a free download, Golden Cheetah v3 and an ANT+ speed/cadence monitor.  You can find a Linux tutorial here http://ubuntuforums.org/showthread.php?t=2177886

If you use Windows or Mac you can get the download here http://goldencheetah.org/download.html