Ah, my old stomping grounds. You live in a great area for interesting anurans - I used to spend nights in Archer County chasing Texas Toads, Green Toads, Spadefoots and Red Spotted Toads, to name just a few. Right now is a good time for the first 3 I just named, after a big rain storm.

Kurt is correct, although he hasn't told you that it could be either a Cope's Gray Tree Frog (Hyla chrysoscelis) or an Eastern Gray Tree Frog (Hyla versicolor). It's impossible to tell by looking at the frog which one it is, unfortunately, and don't believe anyone who says you can - they don't know what they're talking about. With a skilled ear and experience of the two species, you can distinguish them by call, but it's very subtle.