Just spent a few lovely days in sunny Seville (whilst it snowed in London). Mapped as much as possible of the street names of the historic centre, most of which had been traced from Y! and were nonamers. Potlatch's new filter helps alot when editing this way (cheers RF), although I did find I didn't name some highway=pedestrian instances as my printed nonames output didn't show them as such. Also met up for a drink and chat with Pedro, who is mapping his city and showed me his cool Openmoko device.
Some problems mapping in this location: very poor GPStracks due to very narrow streets and tall buildings; very difficult to make judgements on highway types (what I thought were pedestrian streets often had scooters and even vans and cars coming at you); stiff neck from constantly looking skywards to collect road names high up sides of buildings; deciding whether to map names as displayed or to add Calle (went for former); hot work in the midday sun (cafe is good).
There is a free city bike service with many pickup/dropdown points. Would have used it more but time limit is 30mins and you can't immediately re-register for another bike (ie swop and continue). Urban mapping by Segway could be the way forward. Seem to be legal in most of Europe, except UK.