First off, welcome to the DIS! You will find an amazing amount of information here on everything to do with Disney World!
To answer your specific question regarding tickets, you do not have to pay for rides once you have entered the park. You admission ticket allows you to ride rides, see shows, and watch parades and fireworks.
Waiting times for rides depend on several things, including what time of year you go and what time of day it is. Wait times can be as low as 5-15 minutes during slower times of year, and over an hour at the busiest times. What time of year are you thinking about going, and how long do you think you might stay?
A great book to buy is The Unofficial Guide to WDW. You can find it in the travel section in Borders or Barnes and Noble or at
Amazon online. It is written pretty tongue-in-cheek, so if you like that kind of writing style you'll love it (it's my favorite planning book). It covers everything, including getting there, getting around, hotels at Disney and nearby, tickets, how to see the parks, dining options, and pretty much anything else you can think of.
Most of all, come here to the DIS with your questions! There are lots of Disney-planning-addicts here, and helping others plan their trips is our second favorite thing (planning our OWN trips being our #1 favorite thing!).
Also, you can check out
www.disney.com and click on the "travel" tab at the top of the page. That is Disney's own website and can give you a lot of info too.