Wirelessly posted (iPhone 3G (16GB, 2.1 PWNed): Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_2 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5G77 Safari/525.20)
Change language to U.S. English. Should do the trick.
Walking and running distances are almost always done in metres/kilometres.
I wish it was a system-wide option to switch the whole Maps app to metric. Hell, I wish it was an option to switch all the road signs to metric, but I think that's slightly beyond the scope of the iPhone 😉
Really? I just tried my usual journey in to work, and it came up with the most crazy route I've ever seen. (walk 2 miles, get a train in the opposite direction to my destination, get anther train into town, get a bus, walk, another bus...). Usual route is one train!