Try looking into a work visa, Im not too sure on England itself and how they work but Im sure they have one, many other TP'ers have been over there they can help you with that. Gettin under the table work in a pub apperently isnt that hard I have her of lots of people get jobs like that, just make sure you get paid out frequently you dont wanna work 2 weeks and have your employer screw you outta your cash. Ummm as far as teaching tennis, you can always go down too the local club and say your an american pro blah blah blah just run your mouth a bit and see what ahppens you never know. Flights now there is something I can help you on, try www.studentuniverse.com
I find that they are wicked. sta is a nice travel agent cause they have outlets all over the world, make sure if you get a ticket with them its a blue ticket cuase then you can get refunds on cancelations and not lose all your money if you have too cancel.