Thermocouples

Wikipedia Theromocouple
Wire Color Codes and Limits of Error
Wire Insulation Identification and Temperature Range
omega.com - Thermocouple elements
Making a Thermocouple - recomends capactor discharge for welding the junction
DS2760 Thermocouple Kit - $35 1-wire kit w/ K,J,T probe wire
The 1-Wire Thermocouple - Uses a 1-wire DS2760 / DS2762 ~$6
PT100 Interfacing - Analog Devices app. note

Chips

MAX6675 - SPI K-Type D/A Compensated; ~$14
AD594 J-Type Compensated Amplifier
AD595 K-Type Compensated Amplifier