I too have recently gone back to vegetarian eating habits after a while off, and found the book "Vegan: The New Ethics of Eating" to be helpful. It has a bunch of political statements, which you may or may not find interesting, but the nutritional info was pretty helpful. You can download the entire book for free too, which made it appealing to a student on a budget.
I have mainly upped my consumption of soy products to replace the meat proteins that I had been eating, added more complex carbs as fuel for the biking, and make sure I stay hydrated at all times. Other than that, I am eating pretty much the same way that I was when I was eating meat. (and no, I'm not vegan, I just found the info interesting)
Hope this helps!
Kat