In reply to a13x:
The Cyclist's Training Bible by Joe Friel is comprehensive and a pretty good place to start, he also has a blog which is worth trawling through the archives.
The Time Crunched Cyclist (Chris Carmichael) has more specific emphasis on structured high-intensity work (i.e. lots of intervals) to get the most bang for your buck in terms of training time. This probably would benefit you the most by the sound of where you're at now. It's also based more heavily on modern ideas of training with power meter information but still applicable even if you don't have one of those (in which case its quite useful and interesting to "calibrate" yourself periodically on a gym bike or a turbo.)
(I'm guessing the new edition might leave out the name-dropping bits about how he used to coach a certain Texan pro rider though...)