I started Alli a week ago, and after being consistently the same weight for two years, now I am gaining!!!  I have started to exercise at least 45 mins a day and I have followed the fat/cal guidelines to loose weight...What else can I do..or what am i doing wroing?

A couple things to try:

Look at the carbs to see if that could be a problem.

It's possible that the calories/fat grams might be a little high. Try lowering them just a little.

Make sure you are drinking enough water.

My immediate reaction is to say to ask yourself if it's that time, or right before that time, of the month. If it's the case, there's most probably your answer. If not, then check your diet for extra calories and too many carbs, as reptilemom said. You could also be retaining water, so check for salt and chemicals in your new diet.

 They say when you exercise you gain muscle.  Does anyone know if that is true or not?

Yes, exercise will help you develop muscles. How much muscle you build depends on many different factors, including what kind of exercises you are doing and how much protein you are eating.

 Just keep taking the Alli & be as careful as you can. I for the 1st 6 months ALWAYS brought my lunch to work & I only eat out once a month & always make a good choice.  I assure you it works I have been on Alli since August & have lost 48 lbs. After the 1st 2-3 months my weight loss slowed BUT I as long as I take Alli I do not gain back & have continued to lose the weight slowly. Give the Alli a few weeks to really get in your system & kick in.

Are you drinking a lot of water? I have noticed that when I don't drink that much water I don't lose any or just a little weight. Also watch out for salty foods, they can cause you to retain water.

 Check the amount of sodium you're consuming, the # of fat grams and calories. Also make sure that you're getting at least 64 oz of water per day.