The Dallas Semiconductor DS18B20+ is ideal for interfacing to a microcontroller, especially if it uses the '1-Wire' interface which allows looong distances between sensor and microcontroller (200'+!).

It is often used with the PICAXE microcontroller, which has the built-in function "readtemp" to communicate with this device.

The DS18B20+ features:

• 1-Wire interface
• Unique 64 bit serial code so many devices can share same data line
• Data line powered from 3 to 5.5V
• Measures -55 to +125°C (-67°F to +257°F)
• ±0.5°C Accuracy from -10°C to +85°C
• Resolution is user-selectable from 9 to 12 bits deep. That means resolutions of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C!
• Converts temperature to 12-bit digital word in 750mS (higher accuracy takes more time to measure!)
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Packaged in a TO-92 (transistor-like) package, all you need is 2 wires - ground and DQ (I/O & power), or you can use the Vdd line to give it regular power input.

• [Data Sheet]: DS18B20+ Digital Thermometer (pdf)