Camera policy for most the bigger venues in Dallas is "no professional." However most of the venues in Deep Ellum "The Door" included will allow them, unless the band is restricting them.
The Granda Theater allows professional cameras alot of the time, unless the artist has specifically asked them to not let them in. If they artist hasn't asked then they generally allow them. If it's a larger artist playing there, expect them to be restrictive ie: Adele, Cat Power, etc.
House of Blues is no professional without photo pass, and if you do have a photopass and they catch you shooting past the first 3 at a show where the artist is being really anal, they will take your gear away and check it in.
Same thing goes for the other larger venues like Superpages.com Center, Nokia, AAC, Bass Hall, etc.
I actually shot that David Cook show with photo pass, he was killer to shoot majorly playing it up during the first 2 songs. Which was what we were allotted to shoot. I was also excited to see he was using the spots. I've shot there many times and he was the first artist to actually use the dang things.
Here's one of my shots.
Even if you're going to a show at a venue that doesn't allow pro cams, I encourage you to learn to utilize your point and shoot's manual controls. I've shot some great stuff on my point and shoots, and sure it's a tad noisy but that's what they invented noise ninja for right?
for example this was shot on a point and shoot, just to show you the results you can get with some practice.
