How do I block text messages from an LG Xenon phone?

[sunset8949]

Long story short, my idiot of a roommate gave my number to one of her friends who I've never met, and he keeps texting me. It's really annoying me. I would like to block his number from texting me, but I don't know how. I have an LG Xenon phone, AT&T service provider, if it matters. I found the "Call reject" function and put his number on it (though he hasn't tried to call me), thinking it might block texts from him but it didn't. Is there a way I can do that?
Toni - LOL good idea!!!! So far I've been ignoring him. I think he finally gave up. I'll keep your idea in mind though
Toni - LOL good idea!!!! So far I've been ignoring him. I think he finally gave up. I'll keep your idea in mind though