Welcome to the hobby, it's far more fun and exciting with great people than I ever realized. I think if you put in some time to get involved you well enjoy it (note: I'm an HF snob of sorts now, very little VHF/UHF). But be that as it may...
I don't know if you're interested in spending any money, if you are I highly recommend
HamTestOnline™ - Ham Radio Exam Courses and Ham Radio Practice Exams they have study guides and practice tests for all classes of exam from Tech to Extra. I used them to study for my General and my extra and have found them to be a fantastic resource. It's not just memorization they actually give you the study materials too and the system works with you to help you with your weak areas. Of course it's not free but I feel the site was worth every penny I've spent on it.
You can absolutely take both (or all three) exams at once! In fact you will generally find that so long as you pass each exam there is only one exam fee for taking all the exams. The way it works is this.. You sit and take your technician test, it's then graded and checked over by each of the VE's (3 or more in total) and they all sign off on your pass/fail. If you pass you are then eligible to take the next class of exam (General). If you can pass that, you can then go ahead and sit for the extra if you wish and do a clean sweep. I have to warn you though the extra is a *DOG* of a test, an absolute beast.
The good news is, the General gives you access every ham band and the right to use full legal limit power (where permitted). In fact on 10, 12, 30, 60, and 160 meters you have the same exact permission as Extra class operators. On the rest you have significant portions of the phone band open to you and nearly all the data/cw/rtty frequencies as well. So the General is certainly well "empowered", the only band where General might feel a little "cramped" would be 80/75 meters as they're only given a fairly small amount of the phone band. But the truth be told I spend far more time between 20 and 40 meters with the rest of my time on 10,12,15 and 17 meters. 30 and 60 meters are very.. Odd.. Bands.