Looks really good, not too sure about anything thats not anatomically correct as im, not up on my tree frogs!
Have you googled it just to see some images, as reference is king when doing anything organic, or anything thats real to be honest.
I think that you might be able to clean up the "nose" area a bit as it seems you've got a few polys that might not be doing much (think this is because you used a sphere a the starting point)
If your going to texture him, I saw a tutorial on texturing a frog on highend3d, heres the link
It's a different type of frog but i'm sure that you can adapt it to yours.
Also think thst seeing him walk, jupm, climb would be really cool too!
Looking forward to some updates
"No pressure, no diamonds" Thomas Carlyle