Minneapolis is installing "smart" parking meters in the warehouse district. Here's an article explaining the project.
I snapped these photos yesterday, but the meters weren't operational yet. Personally, I think they'll be great (assuming they work). I'd rather use a credit card instead of carrying around quarters.
Coincidentally, there's a good article in Thinking Highways apout parking in Pasadena, CA that talks a lot about parking meters. The balancing act with parking meters is to make them cheap enough that people want to use them, but not so cheap that people will keep circling the block waiting for a meter to open up. Using smart meters will allow Minneapolis to fine tune this balancing act.