Don't know of a site to help but would also like to know. In Canada, we are getting more rules/charges for connections. They are adding a 15 or 7.50 CAD ($10 or $5 US) fee for every connection.

Some cheaper international fares only allow one on-line connection preventing abuse of the 24 hour stopover rule on international flights that could otherwise be used to more cheaply help one hop across the country doing business in a new city every day and have a weekend vacation overseas at the end of that week.