Whew, so many topics to touch on... bear with me.
Lensmith, thanks for the kind words. I wish you were coming to Cancun, 'mano. Here's my take on the Reuters/APTN thing...
KFOG works with me here in DC. What he wrote is perfectly correct, as is Lensmith (paradoxically) - it all depends what part of the world you're in. Central/South America has more available photogs for daily hire due to their much denser television presence - there are more broadcasters there per country (on average) than in Africa or parts of Asia. Luis, in your country alone there are at least three broadcast networks (RCN does their Washington news out of my office - and yes, Sandra is a hottie.) Thus there are more trained photogs available.
The shooters I've met that travel globally are threefold: Bang-Bang Freelancers, staff shooters tied to "The Hot-Shot Foreign Correspondents," and Diplomatic Travel Pool shooters. The rest stay, like Lensmith said, within their region. Just remember - some regions are much larger than others.
We've all met the first group. They're the guys that can bore you with all the conflicts they've been in, but many forgot how to shoot a nicely lit interview. These guys get their gigs by showing up for the war with their gear and then shopping their services around to their clients. Most often we'll use a core group of shooters' material since we have a working relationship with them already. That's why you might meet someone in Afghanistan who says he works for Reuters, since we're his main client. He may very well be selling his video to a German or Japanese network at the same time, it all depends if the video was sold for exclusive use or not. Generally these guys will tell you they work for the best known client they're currently selling to - maybe us, the BBC, CBS, whoever - without being an actual staffer. It's just easier.
The second group are, IMHO, much more interesting. I've met several guys from TV4 Sweden who were the shooters for a reporter named Rolf Something that was their version of Christiane Amanpour. If an event was important enough to warrant their own coverage, these guys were there. Some of the most professional people I've ever met. The burnout factor was extremely high, though. They literally spent 1/2 the year or more living out of their suitcase! Rolf is a great guy, but I met three of his cameramen over time - about one every two years. Nominally they were based in NYC to cover North America, but often they would cover a Cyclone in Micronesia then go to the Stanley Cup playoffs to interview Peter Forsberg then fly to Brazil and do a story on a mission in Rio's slums, por ejemplo. I wonder if Ms. Amanpour has a dedicated photog or if she uses freelancers. I think there are one or two staffers working with her out of London.
The final group - Diplomatic Travel Pool, are a different breed altogether. All they do is follow their Head-of-State/Foreign Minister around. Read the excellent article on this website from a freelancer that went along on Bush's Africa Trip. It's a freakin' grind. 4 Countries in 4 days! No thanks. Besides which, you usually have to be a VERY senior staffer to be part of a travel pool, since the OT is out of this world and we're greedy people.
The guys KFOG wrote about are mainly our African and Asian region shooters. The poster by name of WTN can tell you more of them than I can, but rest assured that we don't have any TV Stringers in Burkina Faso or Chad, so that continent's shooters get a whole bunch of travel.
My race is run. Gotta go shoot a stand-up and edit a 9/11 piece. Yay.