Not to scare you, but I've heard of quite a few snail disasters. One i Witnessed: My friend had only a few visible stow aways that had come along with plants in his planted tank. He tried to pluck them out manually with a spoon & a fishnet, but failed. Within a few months, even with regular (and increased) water changes and gravel vacuuming, his tank was overrun, day and night, All you could see on the walls of the tank were hundreds of snails and slimy little egg pouches. The gravel in his tank was black, and you could see them squiggling through the gravel too. They slowly ate most of his plants from the roots up. He asked for my advice and i suggested maybe he was feeding too much and they were breeding so rapidly because of the excess bioload, but that didn't seem to be the case. Loaches just couldn't do the trick. He had to break down his entire tank, soak everything & scrub everything in bleach, & get new gravel, reassembling his entire tank to finally get rid of them. No lost fishies though.
I think it really depends on your tanks conditions & the breed of the snail. I've had plenty of large apple snails or trumpet snails with no breeding or problems, but the tiny hitchhiking breeds of pond snails & some smaller breeds of ramshorns such may overrun a tank. I'd suggest trying to
ID the species and see how fast they breed & whether or not they are plant-eaters if you have a planted tank.
If you decide to remove them, you could try loaches, manual removal, a chemical solution (not suggested) small increase in aquarium salt added to your water changes (may or may not work - be careful with dose), a homemade snail trap (use a plastic margarine lid with a string tied to it and weight it down with a rock or some gravel & place an algae tab or some fresh veggie piece in it and when you turn off your lights at night, wait a few hours for the eating snails to accumulate on it and snag em all & chuck em - may work, but has to be repeated every night for a long time to catch all the little buggers) or commercially available "snail traps." link from google-
http://www.snailsrgone.4t.com/
I googled and here are some other removal & breed Id links that may be helpful:
http://www.geocities.com/CapeCanaveral/4742/snail_faq.html
http://www.fishpondinfo.com/snail2.htm