If a person is looking for a job then Craigslist is a perfect place to look or to advertise services. The problem for a homeless person is internet access. If a person has a cell phone and is looking to advertise a service like painting, stucco work, carpentry, etc.. then all you would have to do for them is run the ad on craigslist for them. The ads are free and can be renewed indefinitely.
For this ministry to be effective the person needs to have a phone. If you do a Go Phone ministry then this would be a logical ministry to add to that.