1. One person per unit. Okay, this takes care of some people, but there are a lot of homeless families. This doesn't address their needs in the least. Finding shelter for children should be a first priority.
2. Flat screen TVs and computers? Where do homeless people get these? If you're suggesting they come as part of the pod, paid for through whatever nonprofit organization is financing the thing, maybe.
3. Metal sounds unhealthy in both very cold or very hot climates. They'd have to be fairly insulated, and have sufficient ventilation.
4. Put them near public transportation hubs in large cities? I live in a large city, and I can't think of a single area that could house a fair number of these, not to mention a "giant field for recreation, swimming pools, etc." Yeah, can you imagine this in New York City? There is no space.
Some well-known architects have come up with better ideas. Helmut Jahn, for instance, has built this LEED-certified (the top grading for green, eco-building) housing aimed primarily at homeless men (in a neighborhood not far from me). It's powered by a wind-turbine system that sits on top, and the five-story building has units with 300 sq. feet each, a kitchenette and private bath.
Stanley Tigerman has designed another housing unit on the South Side (where there's a lot more land).
http://www.nytimes.com/2006/11/05/realestate/05national.html