php portfolio

I have a kind-of off topic rookie question: most programmers have a web portfolio right? -- a URI to put on their resume that has examples of their work. what do employers expect to see if they ask for such an example? a working web app? links to multiple working web apps? actual code? I am dying to break into PHP/MySQL programming and have gotten a nibble from an employer who is asking for such a URI. I don't have any professional programming experience, but have several small projects that I would like an interested employer to see. what is the best way to present it/them? just a link to one of my finished projects? can an experienced programmer get a strong enough sense of how I code by looking at the end result (probably a dumb question)? thanks, matt