Boingo users will roam onto 1,588 BT OpenZone hotspots: The BT service operates throughout the UK and Ireland, including dozens of airport terminals and lounges. These locations aren't included in Boingo's unlimited usage monthly flat-rate plan, but are charged per minute; they are included in the unlimited SkypeZones calling plan, though.
Roaming is not included in their flat-rate. Almost all locations outside the US are not included. Boingo has two "premium" rates; $0.25 and $0.55 per minute. For example, roaming on French Hotspots for 1 hour will set you back $33,-!!
btw, have you ever noticed that as a UK person you cannot subscribe to the Boingo service...