Are there any websites that can explain/help you create training schedules?

I'm finding I'm more interested in distance than speed when it comes to cycling, but I'm not sure how to properly train for longer rides. I'm planning on doing a ride down here in September-it has a 25 mile & 60 mile option. I know I can do the 25 with ease, but am not sure how to properly train for the 60 mile option.

Thanks,