On the topic of architecture magazines (European for that matter, as I'm ignorant of the American side of things):
'El Croquis', as mentioned by Adam, is a fantastic magazine, though I find it relies too much on Hisao Suzuki's photos. I enjoy them, and his work has a distinctive and remarkable color pallet, but it does get a bit tiresome after several issues. There is some work from other photographers within each issue, so not all hope is lost.
Yukio Futagawa's GA magazines – GA Houses, GA Document, et al. – are also great reference. They span several decades, all photographed by Yukio and his son Yoshio. His photographic documentation is very meticulous, and has for many years inspired other photographers. On issues where american architecture is featured, it's interesting to see a foreigner's view.
Personally, I prefer '2G' magazine, as the photographer changes from issue to issue. In some cases they've been commissioned by the architects, on others by the magazine itself. The recent issue on Mies Van der Rohe houses is absolutely beautiful. The photographs from Hans-Christian Schink escape the norm; there are is no magic-hour images or perspective contortionisms, leading to a very respectful view of Mies' work.
Some photographers that I strongly suggest following:
FS+SG is a duo formed by Portuguese photographers Fernando Guerra and Sergio Guerra. If I'm not mistaken, Fernando's formal education is in architecture, but did a lot of street and travel photography in the early years. As a result, most of his work is with light cameras and if possible, without a tripod. They have been the main photographers of Alvaro Siza's work for some time now.
I discovered
Hertha Hurnaus' work through 2G, and it's enjoyably exquisite. There's a certain irony and amusement in her work that goes back to commercial and advertising roots.
Hagen Stier has a very bold modernist take on architectural photography, often inspired by subjects of similar nature. His images are brutal, clean and direct to the point.
Other photographers are strongly linked to their country's architectural output, such as
Cristobal Palma (Chile),
Duccio Malagamba (Spain),
Nelson Kon (Brazil) and
Paul Ott (Austria). The list goes on, but this might get you started.
As for myself, I still have a long journey ahead as a photographer. I find that this constant research keeps the mind open to new and different things, and helps me experiment on different photographic languages. If I find something that I'm comfortable with, it's time to move on to something different.
Cheers,
Pedro