Michael Spencer has a long, thoughtful post about how Christians should respond to panhandlers, including a list of Biblical passages addressing the subject. He also notes this about church Good Samaritan Funds:
Dave Ramsey tells the story of working with his church’s benevolence ministry. They put three guidelines into place for all people asking for financial or food assistance. 1) Work an hour or two at the church. 2) Meet with a member of the church to make out a budget. 3) Attend one church service. Ramsey says that over 95% of persons asking for financial help did not return when these guidelines were given to them. This is a good indicator of the actual makeup of most benevolence requests.
It's not a bad idea, but most of the people that I've worked with who knock on the church door asking for money are generally on the last day that they can pay a bill before being evicted, or losing their car, etc.
Still, every church needs to think through what its ministry toward such encounters should be. What does your church do?