well your wirless internet should come with some security depending on what network you are with... i use a belkin adaptor with my bt home hub and i have a 10 digit wep key on teh back ofthe hub so ppl cnt access my wirless .. check your hub or modem and it should say wireless key..or if not check you setings and see if you can make one ... hope this helped
Use WPA encryption on your router, and choose a strong pass phrase (i.e. not something that consists of dictionary words, or is otherwise easily guessable).