Really? I'd never consider using a sign-on-intersection advertiser, but I would consider using someone who came to talk to me, though it depends completely on your sales pitch.

My approach wouldn't be "do you have any work for me?" Instead, something more along the lines of "I just started up a business doing on-site computer maintenance and configuration for small businesses like yours, and I'm wondering if you'd be willing to spend some time talking to me about what sort of problems you're facing in that area, so I can get a better understanding of what sort of needs the local businesses have." Listen, and take notes. Thank them for spending time with you, give them your card, and leave. No sales pitch -- the goal isn't to get them to buy something, just to a) let them know you exist, and b) establish yourself as someone who's going to listen to what they're asking for.