What kind of snails are they?
Personally I like some snails in my tank. I have a nice population of malysian trumpet snails at the moment.
So long as you keep your snail population under control by not over feeding your tank they will actually do some good maintenance type activities.
I especially liked the trumpet snails becuase they:
1. burrow in the substrate which is good for it.
2. have hard pointy shells and are relatively loach resistent
3. eat excess food sitting around on the bottom of the tank - so long as the shrimps or cory catfish dont get it first.
4. eat other less beneficial types of snail.
5. eat dead or decaying plant material rather than live material.
6. are live bearers ... how cool is that
the only snails ive had problems with are some of the smaller species of ramshorns which ate holes in some of my plants.
My loaches took care of some, and the trumpet snails seemed to help suppress the rest.