"Any suggestions on a training plan/schedule?"
The plan that I've seen recommended most often, and which has worked phenomenally well for me, is to increase both your total mileage and your long ride by 10% per week, provided you have time, then taper off in the final week so you can store some glycogen and rest your muscles. So if your total mileage in week one was 50 miles, with a long ride of 40 miles, the next week, you'll want to shoot for 55 miles total with a long ride of 44 miles. The following week, you'd shoot for 60.5 miles total, with 48.4 miles for the long ride (I usually just round up and ride a little extra, though -- makes the math easier, LOL).
I think a couple people have probably already noted this, but generally, if you can ride 50-60 miles, from what I've heard, you can probably handle a century. Thus, if you don't have enough time to work up to a long training ride of around 100 miles, you can probably still do a century ride pretty readily.
It will also help to train on terrain similar to that which you'll ride in your century -- if it's hilly, ride tons of hills. If it's hot where you'll be riding, acclimate yourself to the heat (and plan accordingly, and maybe hire one of those water tanker trucks to roll along with you

).
Nutrition-wise, a fellow on bikeforums.net pointed me to this article:
http://www.ultracycling.com/nutrition/centurynutrition.html
After reading it I realized I was not eating anywhere near enough.
I was afraid I would gain a ton of weight if I started eating 3,000+ calories a day, but I've only trimmed down this year — when I got back into riding seriously last winter, I was wearing a size 36 waist, now I'm down to a 32. YMMV, but I think a lot of people make the mistake of undereating when they get into serious athletic pursuits.
I'm convinced that eating like a horse is the main reason I've stayed healthy through a couple thousand miles of riding this year (well, 'healthy' except for the part where I crashed my bike into a lamp-post and dang nigh broke a leg, but that had nothing to do with nutrition and everything to do with me being an idiot

).