Losing body fat can make them smaller, but that can happen regardless and is not directly a result of weight training. My bust is smaller from losing nearly 40 lbs, and while lifting played a role in that weight loss, they would be smaller no matter how I'd lost it. They are also not really smaller proportionally for me because my band size dropped but I still wear a C.
Also, weight training can give you a bit of a boost in terms of looks because more muscle in the pecs can look like more bust and make things look perkier. And remember that you can't spot reduce (you can firm, but you can't really target where you burn fat from) so you won't lose more or less fat from your bust depending on your lifts.
As for programs, I started off doing CF so that's a different option than you're looking at (I am now doing 531). There are several good starter barbell programs out there, but you don't need to find a "women's program". You just need to scale the weight to fit your needs. Starting Strength and Stronglifts are both popular choices for beginner barbell programs but I haven't done either one so can't recommend one for sure. I think Gubernatrix (a women's lifting site) had a good review of program choices.
Also, you will probably want to watch some videos and/or read some stuff on form (Stumptuous has some good ones) and maybe get someone who knows what they're doing to help you get started. A lot of us women didn't spend time in the weight room as teens like a lot of guts do, so we may not have seen or tried some of the lifts before.
My friend who has been strength-training for 6 years (for football) is going to help me with my form today to make sure I don't hurt myself. I will definitely checkout that Gubernatrix. thanks!!
I've seen it happen to fitness competitors who aren't using steroids, but it's only when they drop to super low body fat (which is why some get implants). Again, it's not the weights that do it; it's the person's ultra low body fat levels.
OK So I should probably just avoid steroids and turn my healthy carb intake up a little bit to make sure I don't lose too much fat. Sounds like a good plan.