I agree with Chantal21.....I'm barely pregnant (4 weeks 4days) and stocked up on water and some Sierra Mist......I used to drink a TON of Diet Pepsi....I bought those tiny little cans (like 6 or 8oz) and have one every 2-3 days just for the taste of it! I think that as long as you limit it, it's OK...get like a small one twice a week or so.....
My midwife told me I could have one beverage a day with caffeine in it....so I could have a coffee if I wanted or juice or soda. I rarely drink any caffeine though, but like twice a month I have to have my Starbucks frappuccino fix!! =) I would just limit your intake. Make it a special treat for yourself. Maybe only have it once or twice a week. There is no safe limit. I believe everything in moderation! =)