a list of the world's budget airlines.

Australia, New Zealand and the Pacific: Virgin Blue and Jetstar, Freedom Air
India and Sri Lanka: Air Deccan, SpiceJet, GoAir, and IndiGo Airlines. Also Kingfisher and Jet Airlines.
South East Asia: Tiger Airways and Jetstar, Asia Airways, Nok Air, Adam Air, Air Asia and Lion Air
North America: Southwest Airlines, Spirit, Air Tran, JetBlue, WestJet (Canada), Club Mexicana (Mexico)....you know
South America: Gol, BRA and Ocean Air.
Africa: Kulula, Precision Air.
Middle East: Air Arabia, Jazeera Airways.
Europe: Ryan Air, Easy Jet, SkyEurope, and Air Berlin. Oasis, Zoom


For bookings: I personally am a fan of Vayama...if Kayak has not your flight route.