Everyone is prepared for the "culture shock" of going to Latin America, but it is often the return home that is most difficult. Few people will understand what you have experienced -- though most will be fascinated -- and after several months of working in the favelas of Brasil or the pueblos jóvenes of Lima, you may find prosperity hard to take.
One way to overcome this change -- and to help the program to which you have dedicated such time and effort -- is to keep working for street children in your own country. For the staff of Mundo Cooperante, a Spanish NGO made up of former volunteers from Niños de Papel, this work has become a full time job. Other former volunteers have raised funds through raffles, bake sales, and other fund-raisers. Some write articles for local papers or record interviews on local radio. Yet others have developed websites for the programs where they worked.
Make sure that you have good communications channels with your new friends and with the organization where you volunteered. If you are going to raise money, find out about tax deductions and figure out a way to transfer funds internationally: Western Union and similar wire services can take as much as 20% of the money you raised!
Be creative, and remember that your work as a volunteer does not end when you get on a plane back to your own country.