Are you looking for a location where you take the photo yourself, like an outdoor location? Or are you looking for a photography studio?
I'll give you a referral to both. =)
In Plano, off of Legacy and.... between Independence and Coit, there is a trail that runs for 7 miles. Along the train there are some GREAT spots to take photos. If you have a bike, I would just get out on your bike and ride along the trail and find a spot you like. Frankly, right off the trail on Legacy, between Independence and Coit (there's no street, so I can't tell you exactly where it is), would be a great place to take an outdoor photo because there are lots of trees there.
As for an indoor place, I recommend Kiddie Kandids in Stonebriar Mall. They take great photos at a great price for the holidays!
Good luck,
J.