Just setup WPA, it is easier than WEP and more secure. Once you have it setup, hide the SSID that will prevent most devices from attempting to connect, if they try they will be presented with a popup requesting the pass key.
WPA-TKIP is subjected to Brute force attack, if a dictionaly word was used and 8 chr or less. Use WPA Personal (AES) if available. Use a random generated 20 chr string using all printable chr. I use the free password generator on
www.grc.com I found a site that determined the probability of brute force. 20 chr of all printable chr was over 24 yrs at 100k/sec rate. So you can say these are pretty safe. If you have a router that supports WPA2 use it instead. It use the key you provide and generated a ket it self and combines the two. The on a set number of min/sec it changes it's 1/2 so the key is always change eliminating the posibility of hacking the key.