In the words of one of our more prolific but recently absent posters... ride lots.
But seriously a study sometime back on aerobic fitness showed 4x/week led to vastly improved conditioning over 3x/week. It also indicated that while 5x/week led to a fitness improvement over 4x, the increase wasn't as drastic as goin from 3 to 4x. What does that mean? most folks interested in competing could benefit from 5x but 4x/week showed some very nice benefit. An hour or more is ideal, but we all obviously have schedules and obligations. Do what you can and keep having fun, whether you are racking up 5 hours a week or 25. Even the toughest riders need some time off the bike once in awhile Beyond that cycling can be as easy or complicated as we make it. But one paradigm seems to hold true with most successful plans: Overload, Consistency, and Moderation,
Not to bust yer bubble but two times a week may show some improvement starting from ground zero, but it's not an ideal frequency to find your true potential. However before any formal training plans I would recommend squeezing the fitness that comes along with 4 weekly 1.5-2 hour rides. You will be very surprised how good one could get on that load - certainly strong enough after a few months to participate in entry level racing and have some fun if you want. To be competitive will probaly involve some additrional speed workouts, etc. and add some mileage.
As far as materials, Joe Friels Training Bible is a good place to start. And just start reading threads in the Training section of the forum. You'll see as many different approaches to training as their are members.
There are no magic bullets to training, you want your body to get stronger on the bike, you'll need to spend time on the bike. IMO with the exception of core exercises like planks, ab work, etc, which are helpful for riding comfortably in agressive positions, there is absolutely nothing that needs to be done off the bike to get faster on the bike. Zilch, nada, de rien.