bandwidth LImit

Dear all,

Now i have a problem of limit the bandwitdh for my friends to use ..
I am currently on a wireless connection and would like to limit my
other users to 300 kbs only and i want tohave the remaining 700kbs
connection ..

CAn you guy tell me what to do in order to limit the connection of it
?
i mean should i download some special software or may be make a server
to control it .. or is there any thing i can do to make it possible..
?

Thank you in advance ..

REgards,
Billy