Two major scientific journals are just releasing special issues focused on Web surveys. Sociological Methods & Research is just out with an issue that has several interesting articles of potential interest to Web survey aficianados including two on propensity score adjustment. Public Opinion Quarterly also has a new special issue devoted to Web surveys. It includes some interesting research from Europe where some of the best methodological work is being done.
In case you missed it, the Journal of Offical Statistics dedicated an issue to Web surveys in June, 2006.
The POQ issue is available free to AAPOR members. If you don't subscribe to SMR you will need to find a library or a friend who does.
It's encourgaing to see this upswing in serious academic research about Web.