need to know how to check and see if anyone is on my wireless signal?

Airsnare

http://home.comcast.net/~jay.deboer/airsnare/

Debo ... I'm sure the other suggestions you'll receive will work. But how about a simple, low-tech method too? How about just suspending your traffic by letting your system get idle or if you've got a firewall, select the setting that will block all traffic. You can also momentarily disconnect your system from the router.

After you've stopped all in-coming and out-going traffic on your computer, watch the connection/status lights on your modem or router. If someone's using your wireless connection, the status lights will flash to indicate that traffic is being sent or received.

Hmm...I'm not sure there is a way to tell if someone is using your wireless signal, but you're connection would be slower if someone was stealing your wireless. Secure your network.