becksA

I can't help you on the dieting side, I've been much better, but I still have my late-night carb cravings. I just make up for it by doing incredible amounts of cardio.
In regards to the exercising, and sticking to it. I know exactly what you mean about motivation. Several times in the past I've tried exercising regularly, and I start out on a good schedule, and keep it, but I end up slowing down and finally stopping. My first problem was exercising in my own house. It's distracting, I dont know, something about it is not condusive to regular exercise. I would highly recommend joining a gym with great facilities, even great showers, lockerooms, etc are all important (at least to me). They keep me motivated, keep me coming back.
It's like quitting smoking or something, the first few weeks are the hardest. You won't notice results really so you'll become discouraged and that's where the motivation drops off. You need to force yourself to keep going, like I finally did and within a month I began to notice results. The more I noticed, the more often I went, and it became a cycle. Now I am addicted to it! Especially with the weather so bad, it's my oasis. I go at lunch for my weights, then at night when I have a lot more time, I go straight from work, do an hour of cardio while I watch TV or listen to music, then sit in the steam room, or hot tub...treat myself.
Another reason I joined a really nice gym besides what I mentioned, is the price. Because of how nice it is, I pay top dollar, so in the beginning, before I really started to look forward to working out, I kept telling myself "you better use it, you paid so much for it"...
But basically get yourself through that first month, then you'll find yourself increasing the levels on the machines, increasing your days, and especially in conjunction with a better diet, you'll start noticing results.