SHT75 from Sensiron is a fully calibrated (calibration constants are programmed individually to each sensor) digital output sensor. It has a I2C like (not compatible with I2C) interface. The sensors are really accurate. I have noticed three sensors close to each other giving an output only deviating by 0.1C of each other.
The attached source code is derived from an application note provided by Sensiron for interfacing SHT7X sensors to 8051 microcontrollers. Please note this code has temperature/humidity conversion coefficients for older (prior to V4) SHT75 sensors. If you use a newer V4 sensor update the conversion coefficients. The code was written for a PIC18F4580 IC and was compiled with HI-TECH PIC18 compiler.