worlds dumbest laptop travel question

[mermaidnz]

please dont laugh if this is something thats really obvious....

so, im going to take my laptop (a mac thingie) and apparently it is wifi enabled, do i need anything to make it work? like if i go to a starbucks or somehting with free wi fi will it just work?

second dumb question, some places may not have wifi, so, can i go an internet cafe and just plug my lappy into their internet and it will work?