Wireless Broadband for Laptops

hi,
im thinking of going wireless for my laptop, but i havent got a clue about any of the things i need for it, and what prices things are. i currently have tiscali broadband (not wireless) and thats all i can really say, as im not the biggest technology knowledge person around. has anyone got any information that would be helpful please, if so i will be really thankful for all your help.
thanx
claire