When I first hopped on the internet back in 1995, the first thing I searched for was - of course! - "sandcastles." The results that came up back then had nothing to do with making castles out of sand.... but there are sure a lot of beach resorts with that name.
Well, since then a lot of good information and photos of fabulous sand sculpture have appeared on the web. The links indexed from here are the ones I find to be most interesting and useful.