Hi! We stayed at the YC last month with our 4.5 yr. old DS...and he loved the pool! Even asked (while in MK) to go back to the hotel so he could play there.
The toddler/kiddie pool is on one side of "Stormalong Bay" and the larger pool is on the other...separated by a walkway with bridge and windmill over the two and the rock/grotto area where the hot tub is located. It's beautifully landscaped and there's lifeguard stations all around. As you first walk into the pool area, there's usually a CM there to check room keys and hand out towels.
Beaches 'N Cream...the terrific ice cream parlor...is halfway between the BC and YC - just across from the pool. And an arcade is just next to Beaches 'N Cream.
They have buckets and shovels for kids to use in the sandy beach area which kind of in the middle of the toddler pool area....the kids can go in and out of the water and back onto the beach...since the bottom of the pool is actually sand, too (a big, graunluar type of sand).
The larger pool area has the big shipwrecked ship/water slide...but we didn't use it, as DS is just getting his "sea legs".
There are lots of tables, reclining chairs all around the pool area, with the usual pool-side service for drinks, etc.
The new pool area at the Poly is going to be very nice, too, from what we've heard...but for now, this has to be one of the best pools for little ones at WDW. Hope you have tons of fun!