First off, Welcome to the site. I'm not a huge poster on the site but i'm a huge thread stalker lol.
Anyways, its good to hear that you want to make a change in your lifestyle. There are 3 main things to changing, which it sound like you have kind of an idea.
1. Diet
2. Workout Routine
3. Motivation and dedication!
Diet shouldn't scare you. The main key is to eat healthy foods, and control your portion size. As for calorie counting, here is how I did it for myself:
calculate your daily calorie intake to maintain weight
then subtract 500-750 calories off that
which gives you what your daily calorie intake should be to lose weight. To help track calories, I recommend
FitDay.com Its great for keeping track and its free!!
As for the nutrition part, here is some links to threads on this site that you may find helpful, they helped me:
"Nutrition 101":
http://training.fitness.com/nutrition/nutrition-101-a-32846.html
"Lv's Grocery List":
http://training.fitness.com/nutrition/lvs-grocery-list-19098.html
Obviously, its going to be recommended that you get your cardio in at-least 5-6 days per week.
As for routines, the main thing is to focus on your whole body. Compound exercises are the best way to start, IE: Bench, Squat, Military Press, Hang Cleans. However, I wouldn't completely focus on weights. Also throw in push-ups, sit-ups, pull-ups, and other body weight exercises, because those will help condition your muscles. Finally, I would also say throw in some resistance training exercises for individual muscles. You can use resistance bands and do curls, or if you want to use dumbbells you can as well. I like using resistance bands for curls sometimes, because I can go through the whole range of motion, and feel like I just worked the whole bicep.
But anyways, I recommend putting together a mix of these exercises. Do some research on routines, 5x5 routines, or 3 step pyramids, or drop-set (not recommended for beginners), ect, and then use the exercises that you feel will impact you.
Make sure you are doing things you enjoy at the gym or when you workout, it helps you stay motivated. I dreaded going to the gym when I first started, but I finally have a routine that I enjoy.
Good luck! if you have any additional questions feel free to ask, and If something in my post is way off, someone will correct me but I think i'm pretty damn close, so crank your ipod, and get your sweat on!