Processing politics & film facts
Depending on where you are travelling to, film considerations will be more or less important. If you're touring the cities of Europe, for example, where high quality film is widely available, pre-planning is not anywhere as important as say, trekking to a backwater town in Thailand's highlands. If in doubt, stick to rule number one - bring your own film, and oodles of it.
In many developing countries, the quality of film is of a poor standard, and extremely light-sensitive film is hard to come by. The best approach is to estimate how much film you intend using, and take double the number of rolls on your travels, including several ASA 400 and 800 films. These are invaluable when shooting in museums or historical buildings where flash photography is not allowed, or in other situations that demand light-sensitive photography.
Be careful with your films when in transit, as films can easily be affected by extreme heat or x-rays. Never pack films in your checked luggage, as the x-ray machines used to screen checked luggage may fog your film, so ensure that films go into your carry-on bags.
Processing problems are common in foreign countries, especially economically depressed countries where the standard of technology is more basic. The jury is still out on the pros and cons of processing film abroad, and it all comes down to a matter of choice. Either way, it's risky - while you may not feel safe leaving your film in the hands of a stranger, carrying films in tropical countries for extended periods of time can be just as dangerous.
If you choose to develop your films then and there, look out for the automated Fuji, Kodak and Konica minilabs in processing shops - these should provide you with an acceptable level of quality