I did. We had our wedding right before I started trying. I didn't lose the weight intentionally, but I have a tendency to eat significantly less when I'm really stressed out. With the wedding, and starting a new job, I lost about 8 pounds in about 4-5 weeks, which is a lot for me because I'm a small person. It ended up really screwing up my first cycle right after the wedding, and although I got pregnant right after that, I miscarried very early on. Since then, I brought my weight up a little, just to be on the safe/healthy side, and I got pregnant again right away, and all looks good so far with the pregnancy.
If you're overweight, it is a good idea to lose some weight for when you get pregnant because it's healthier for you and the baby. But, make sure you do it in a healthy way, because otherwise you compromise your health and the baby's health, if you get pregnant in the midst of unhealthy dieting.