A source for the plastic detector: Rexon Components.
Another Source: Bicron Plastics. A pdf of some of their products.
GammaWatch makes a very neat watch/radiation detector for $250. Unfortunately they are currently out of stock.
This is kind of cool but it is not very sensitive. It will warn you of very serious hazards:
NukAlert #153; nuclear radiation detector / monitor keychain alarm
This is your more normal type meter. It is sensitive but will be off scale in very high radiation areas. The solution to that? High tail it out of there.
Digital Geiger Counter with Wand & PC (serial) Output
Cross Posted at Classical Values