yeah, my sisters dog was VERY irrate when we'd go to clipping his nails (but maybe that's because he got nipped a bit close once or twice) anyway, he would growl at you and we'd need at least two people holding him down, with a third person cutting AND have him wear a muzzle just to do it! I'll never know how the vets do it, they'd get him in and out just like it was nothing!
The dog she has now isn't so bad, but he will complain from time to time. The best thing is to encourage them, pet them and rub their bellies, give treats - makes them look more forward to it, even if they may have gotten clipped before.
One of the best ways to get a dog to have pleasant associations with having any part of its body touched is to use food. If your dog is food motivated then this may work.This will of course only work provided your dog has no medical reason for crying out when you touch its feet.
Have some very very delicious and smelly treats ready. Wait until your dog is relaxed, and then touch a foot very briefly, maybe with just an index finger and give the dog a treat straight away. You could start with one foot and then work your way around to each foot in time. When your dog learns to expect a really tasty treat when your finger touches a paw, then you could lengthen gradually the time that you touch the paw, and gradually go from just a finger to your hand, etc. Hopefully by using the treats, your dog will learn that there is nothing so bad about having its feet touched.
However - it is very important that you DON'T give the treat first and then touch the paw. The dog then learns that when mom gives me a treat, something nasty happens. You want him to get the nasty thing first and the nice thing afterwards. This should teach him to tolerate the so called "nasty" thing in the anticipation of the nice thing following.
Its not a quick fix but if you have time and patience it might work.