I have had snail issues in the past and have found many things that work
1st off if you have any plecos (or anything else you feed alge wafers to) then getting rid of snails is very hard as they LOVE the wafers, however what I did is take a small cup and place a couple of wafers inside right before you turn off your light for the night, then 1st thing as the light comes on the cup will be filled with snails and you can CAREFULLY remove the cup. Doing this a couple of times with some gathering of the obvious snails (i.e. with a fishnet) can get rid of most of them or as least help a great deal to control them.
The other thing I have noticed lately is I got some Tiger Barbs, and by feeding them a little less, they will eat the young snails. I donno if this is common but I do know they have cleaned up what I missed very well.
Loach's are great for this as well as Sam meationed however as he brought up it really depends on your tank size and what you already have.