Hiya Haniif.
The major security issue for Wi-Fi is the RF side of it. That any1 with the right equipment can sniff out data-transmission on the immediate premises.
This is very easy to do, all the user has to do is set his/her wireless NIC on DHCP and they are set.
Its not as easy as it sounds, there is access control, and security protocols that are to be complied before some-one is permitted into the network. Mind you that there is, free access points (public access points?) that any1 can connect to; and then there is private access points that are highly secure, and impenetrable.