There is nothing to worry about with an anterior placenta. I had one for DS1. And as NikW said, it wont move. The "moving" placentas that you hear about are when someone has a low lying placenta (placenta previa) close to the cervix. And with them, as the uterus grows, they can move away from the cervix.

As for movements, well it is most likely that you wont really feel too much till around 20-22 weeks, and when you do, they may be less that how people with a posterior placenta feel them. But you will feel them. And aftger having a posterior placenta this time round, when you get to the last few weeks, I must say I miss my anterior placenta. hehe

Good luck with the next phase of your pregnancy.