Here's what I would do. It's REALLY geeky and would require a fairly trivial amount of programming (assuming you have some knowledge of writing code):
I already use a $35 Arduino microcontroller board with an LM34 temperature sensor to feed temperature data to my computer. A Java application that I wrote does the serial communication and data display. With slight modification, the Java app could dump sensor output to an HTML file in the server's /www directory about once per minute.