As you can see from the WIP pic below, I've built only half of the frog so that I had only half of the UV map to deal with.
Once happy with the low poly model, it was the time to make the UV map.
For the main (half) body and the leg, I've made 2 cylindrical maps, for the feet I've used 2 planar maps: 1 from the top view and one from bottom view. I've used a simple checker applied to a lambert shader for checking the overall process while tweaking the UV's.
After that I've duplicated the half and combined all ending up with 1.960 polygons, quite good for the low poly model (this then can be used as a cage for the rigging/animation process).
I've than duplicated the frog keeping the low model in another layer, and I've made the higher poly version (about 30.000 poly) doing a polysmooth. Finally I've added some details using the Maya sculpting tools trying always to follow the main reference.