I need some info on Prozac...

for my sister. She's been on it for over a year now, due to depression. She lives in the Pacific Northwest and the long rainy winters have gotten to her. I'm hoping that, come Spring, I can hopefully help her to get off of it...(she already said that she will not discontinue it at this time)
So...I'm looking for info on the long term effects of this type of drug, how best to wean oneself off of it, and other methods of dealing with Seasonal Affective Disorder...
Any recommendations on Lightboxes?
The tough part is that she really feels that the Prozac saved her...I feel that she is over the hump now and needs to move on...
And the REALLY tough part is that I am the Elder sister and I have been bossy in the past although not so much in the last 10 years or so. I need a way to not go back to that method of communication, it really wasn't effective... :)