I just went thru this with my 2.5 year old daughter. We started taking her the very first second we woke her up (we never waited for her to wake up). She would go and then every 1/2 hour we'd take her. The key is not to ask, but to just say "it's time for potty". Once he gets the hang of going, he'll start telling you that he doesn't have to go. When it gets to that point, have him go every 45 minutes and then every hour. My daughter has been pretty good, so for the most part, she tells us now that she has to go (it's 3 months into training). We do have her go before nap and bedtime as well as before we leave to go somewhere.
Now, if we go to the zoo, and we put a diaper on her, she will wet her diaper. So, my suggestion would be to only have diapers/pull ups only on at night.
As for pooping... yeah, that takes time. My daugter would refuse to go and would always go in the diaper or in her undies. When I asked her why she didn't want to go in the toilet, she said she was afraid. But, once I explained it's the same thing and feeling if she goes in her diaper the only difference was that one is in the diaper and the other falls in the water. She started going on the pot, but would aways ask us to kneel so that she can lean on our shoulder to go.
My son is 4.5 and has only gone poop at daycare once. The reason being is because he thinks he'll fall in (she doesn't have a child seat). So, make it comfortable for him. You may even want him to see you and your husband go - just to assure him that it's normal.
Oh, and if he likes M&Ms, let him know if he goes poopy in the toliet, he'll get X amount of M&Ms and be extra excited when he does go.
In the end, he will learn, it just takes a bit longer.
Oh, and avoid public bathrooms with automatic flushers. Kids are way too small and it will really scare them if it goes off while they are on the pot.