I've been trying to polinate my alto for a year & a half.. So far no luck. Realized I've never taken the pollen anywhere, so that's what I'll try next.

I do believe it's sterile though.

I now have nice plump fruit on my alato, the baby fruit is doubled in size.. yippee!!! Does anyone think that the offspring from the seeds will be viable??

No! Sorry.
The P. alata x P. caerulea cross has been done a number of times-see link below for more info and to confirm that is the correct ID for your plant. As far as I know they are all sterile but I have heard before of one of the variations in USA producing fruit-which unfortunately will be empty...but you never know. Try and set as many fruit as you can and then open one up after a few weeks to see if anything is happening.
Myles

Here is a link that might be useful: P. x belotii

Thanks Myles, I was sure that this simple of a cross had been done, but I have to wonder if I kept at it and pollenated every cross with a viable pollen, what would I come up with? Would at any time the friut be viable?? LOL.. I guess this is what they call Hybridizing??