[Haskell-beginners] Haskell and TimeZones

Hi, How does Haskell handle TimeZone? Do I need to use Oslon to have a historical database of TimeZones in Haskell? I tried reading the package description and everything, but it seems complicated. Is there any easy to follow tutorial available? For example, here in Brazil the daylight savings rules change every year. How do I update the Haskell Data.Time.* packages to know of the new rules? Or does it uses the TimeZone database from O.S.? I'm looking for a solution that works in any platform (mac, linux, windows). Thanks, Thiago.